Yes, you can change your will if your spouse has dementia. The law looks only at your mental state when you sign, not your spouse’s. As long as you understand what you own, who your close family members are, and how your document distributes your property, you have every right to revise beneficiaries and rework your estate plan. What the law does restrict is how far you can go in cutting your spouse out, and how you should structure anything you do leave them.
Your Capacity Is What Matters
The legal standard for making or changing a valid will is called testamentary capacity, and it focuses entirely on the person signing. Courts start from the assumption that an adult is competent. Anyone who challenges the will later carries the burden of proving otherwise.
The bar is lower than most people expect. At the moment you sign, you need to understand four things: that the document is your will, the general nature and value of what you own, who your closest family members and natural heirs are, and how the will distributes your property among them. You do not need flawless memory or sharp cognition across the board. Mild forgetfulness or early-stage cognitive issues do not disqualify you, as long as you grasp those four elements during the signing itself.
Your spouse’s dementia is legally irrelevant to your capacity. The two inquiries are completely separate.
What You Cannot Do: The Spousal Floor
You can change your will, but you generally cannot use it to disinherit your spouse entirely. The law provides a financial floor for surviving spouses, and that floor applies whether or not the spouse has dementia.
Elective Share States
In roughly 41 states that follow a common law property system, a surviving spouse can claim an “elective share” of the deceased spouse’s estate. Even if your will leaves your spouse nothing, someone acting on their behalf can go to court and claim a minimum percentage. One-third is a common benchmark, though the exact figure varies.
Some states use a version of the Uniform Probate Code, with a sliding scale tied to the length of the marriage. The share starts small for short marriages and climbs to as much as 50% of the marital-property portion of the estate after 15 or more years. The elective share is never automatic. Someone has to file a claim in court within a statutory deadline, often six months after probate opens.
Community Property States
Nine states use a community property system. Most property earned or acquired during the marriage already belongs to both spouses equally, regardless of whose name is on the title. Your will can only direct your half of the community property, because your spouse already owns the other half outright. Separate property, meaning assets you owned before the marriage or received individually as gifts or inheritances, remains yours to distribute as you choose.
Who Claims Your Spouse’s Share If They Cannot
A surviving spouse with dementia obviously cannot walk into court and file an elective share claim. Someone else has to act on their behalf.
If your spouse already has a durable power of attorney covering financial and legal matters, the named agent may be able to file the election. The critical word is “durable,” meaning the authority survives the principal’s loss of capacity. A standard power of attorney becomes worthless once the person who granted it is incapacitated. Many states require the agent to get court approval before making the election, since it is such a significant financial decision.
If no power of attorney exists, the court can appoint a guardian or conservator to manage your spouse’s affairs. The guardian can then petition for authority to elect against the will, and the court weighs whether the elective share serves the incapacitated spouse’s best interest given their financial needs, existing resources, and cost of care.
This is why establishing a durable power of attorney early in a dementia diagnosis matters so much. Once your spouse lacks the capacity to sign, court-supervised guardianship becomes the only route, and it is slower, more expensive, and less private.
Assets Your Will Does Not Control
A will only governs assets in your probate estate. Many of the largest assets married couples own never go through probate, and changing your will has no effect on them.
Jointly Held Property
Real estate, bank accounts, and investment accounts held as joint tenants with right of survivorship pass directly to the surviving owner at death. A home owned as tenancy by the entirety, a form of joint ownership available only to married couples in many states, works the same way. Whatever your will says, the title controls.
Beneficiary Designations
Retirement accounts like 401(k)s, IRAs, and 403(b)s pass to whoever is named on the beneficiary form filed with the financial institution. Life insurance policies work the same way. These designations are contracts, and contract law overrides your will. If your will leaves your retirement account to your children but the beneficiary form still lists your spouse, the account goes to your spouse.
Employer-sponsored retirement plans covered by federal law add a wrinkle. Your spouse is automatically the default beneficiary, and you generally cannot name someone else without your spouse’s written consent.1Internal Revenue Service. Fixing Common Plan Mistakes – Failure to Obtain Spousal Consent When your spouse has dementia and cannot provide informed consent, changing the beneficiary on a qualified plan becomes legally complicated and may require court involvement. IRAs are not subject to the same federal spousal consent rules, so you can typically change an IRA beneficiary without your spouse’s signature, though some states impose their own community property protections.
Better Ways to Leave Assets to a Spouse With Dementia
Leaving a large inheritance directly to a spouse with dementia creates two problems. They may not be able to manage the money, and the inheritance could disqualify them from Medicaid and other programs that pay for long-term care. Trusts solve both.
Testamentary Special Needs Trust
A special needs trust (also called a supplemental needs trust) holds assets for your spouse’s benefit without those assets counting as your spouse’s own resources for Medicaid eligibility. A trustee you choose manages the funds and uses them for things that improve your spouse’s quality of life beyond what government benefits cover: private-room upgrades, personal care attendants, specialized therapies, recreational activities.
When you create the trust in your will for your spouse’s benefit, it counts as a third-party special needs trust, because the money comes from you rather than from your spouse. That distinction matters. A third-party trust does not have to reimburse the state for Medicaid benefits paid during your spouse’s lifetime. When your spouse eventually dies, the remaining assets pass to whatever beneficiaries you designated, typically children or other family. A first-party trust, by contrast, must repay Medicaid before any remaining funds are distributed.
A trust created within your will is called a testamentary trust. It does not exist while you are alive. It springs into existence at your death, funded by whatever your will directs into it. You keep flexibility to adjust the terms as long as you are living, and you avoid the complications of transferring assets during your lifetime.
QTIP Trust
A qualified terminable interest property (QTIP) trust is another option, particularly useful when you want to provide for your spouse while controlling where the assets ultimately end up. The trust pays all of its income to your surviving spouse at least once a year. Your spouse cannot touch the principal or redirect it to anyone else. After your spouse dies, the remaining assets go to the beneficiaries you named when you created the trust.2Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse
This structure is especially useful if you have children from a prior marriage and want to make sure your spouse is cared for without the risk that assets drift away from your intended heirs. The QTIP trust also qualifies for the federal estate tax marital deduction, so assets transferred into it are not taxed at your death, only when your spouse later dies.2Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse For 2026, the federal estate tax exemption is $15 million per person, so the tax benefit matters primarily for larger estates.3Internal Revenue Service. Whats New – Estate and Gift Tax
Medicaid Timing
Dementia often progresses to the point where full-time nursing care becomes necessary, and Medicaid is the primary payer once personal resources run out. Medicaid reviews all asset transfers made within 60 months before an application. If assets were given away or sold below fair market value during that window, Medicaid imposes a penalty period of ineligibility, calculated by dividing the total improper transfers by the average monthly cost of nursing home care in your state.4Office of the Law Revision Counsel. 42 USC 1396p – Liens, Adjustments and Recoveries, and Transfers of Assets
The lookback applies to transfers into irrevocable trusts too. Funding a trust less than five years before your spouse applies for Medicaid can trigger the same penalty as an outright gift.4Office of the Law Revision Counsel. 42 USC 1396p – Liens, Adjustments and Recoveries, and Transfers of Assets Testamentary trusts sidestep this issue entirely, because the assets do not transfer until your death. Nothing is being given away during your lifetime, so there is nothing for Medicaid to penalize.
After a Medicaid recipient dies, the state is required to seek reimbursement from the estate for nursing facility and related costs. States cannot pursue estate recovery while a surviving spouse is still alive, and they cannot place liens on a home where a spouse, minor child, or disabled child is living.5Medicaid.gov. Estate Recovery If you die first and your spouse is receiving Medicaid, the state generally waits until your spouse also dies before pursuing recovery.
Protecting the New Will From a Challenge
Changing a will while your spouse has dementia can invite scrutiny, especially from adult children who may suspect you are acting against your spouse’s interests or being influenced by a third party. Documenting your capacity during the signing process can head off expensive litigation.
Every state requires witnesses, and they serve a specific purpose: confirming that you are who you say you are, that you appeared to understand what you were signing, and that nobody was pressuring you. Witnesses should be disinterested, meaning they do not inherit under the will. If a witness is also a beneficiary, a court can void that person’s inheritance on the theory that they may have influenced you.
Having your attorney present during the signing adds another layer. The attorney can ask you about your assets, your family, and your reasons for the changes. Those answers become evidence of your mental state if the will is ever challenged, and some attorneys take detailed contemporaneous notes for exactly that reason.
Video can be a powerful piece of evidence, but it cuts both ways. A clear, coherent recording of you explaining your decisions makes a will contest much harder to win. But if the recording shows confusion, coaching from off-camera, or an attorney who fails to ask meaningful questions, it becomes the strongest evidence against the will’s validity. If you record, make the process genuinely thorough rather than staged.
A no-contest clause (sometimes called an in terrorem clause) can discourage frivolous challenges. It states that any beneficiary who contests the will forfeits their inheritance. Most states enforce these clauses, though many carve out exceptions for challenges brought in good faith with probable cause. A few states, including Florida, refuse to enforce them altogether. The clause works best when the potential challenger stands to lose a meaningful bequest by filing suit.
A separate capacity evaluation is worth considering. Having your own physician or a neuropsychologist document your mental competency around the time of signing creates strong evidence against future challenges, especially if you are older or if anyone might argue that your spouse’s condition somehow affected your judgment.
Before You Sign
Review every asset you own and confirm how it transfers at death. Go through beneficiary designations on retirement accounts, life insurance, and any payable-on-death or transfer-on-death accounts. Those documents override your will, so updating the will alone may not accomplish what you intend.
Coordinate the will changes with Medicaid planning if your spouse is receiving or may eventually need long-term care benefits. A testamentary special needs trust can preserve eligibility while making sure your spouse benefits from your assets. An attorney with experience in both estate planning and elder law can structure these documents to work together rather than at cross-purposes.
Confirm that your spouse has a durable power of attorney and a healthcare directive already in place. If those documents were never executed, or if the existing power of attorney is not durable, a guardianship proceeding may be the only path to managing your spouse’s legal affairs after your death. That is a far more expensive and intrusive process than putting the documents in place while your spouse can still sign them.