Can You Contest a Will if Someone Has Dementia?

A person can contest a will if they believe the person who executed it was suffering from dementia at the time. However, whether the testator’s dementia is sufficient to invalidate the will depends on many factors, such as the nature and severity of their dementia symptoms. 

Is a will legal if the person has dementia?

Yes, a will is legal if the person creating it has dementia as long as they have sufficient mental awareness to satisfy the relatively low legal threshold known as “testamentary capacity.” 

In California, under Probate Code 6100.5, a person is not mentally competent to make a will if they do not have sufficient mental capacity to understand the following:

  • That they are making a will
  • The nature and extent of their property
  • Their living descendants, spouse, and parents, and those whose interests are affected by the will

As long as the person with dementia has a basic understanding of these ideas, they have the mental competency to create a will. It’s important to note capacity is only important as of the time the will is created.  Later incapacity will not affect a will’s validity. 

Sometimes when there are concerns about whether someone with dementia has the testamentary capacity needed to create a will, with the assistance of their estate planning lawyer, they will take steps to shore up the validity of the document, such as by having a capacity determination done by a licenced or treating physician, perform a capacity examination or test, or otherwise document or memorialize their abilities and desires to do the planning at issue.  Sometimes videotaping a Q & A with the testator can help support the validity of the document, but oftentimes the videos show a frail and somewhat incoherent testator, which, in the hands of an experienced probate litigator, only serves to help invalidate the will at issue. 

Can people with dementia contest wills?

Yes, people with dementia can contest wills as long as they are an interested party in the will and have the necessary “legal capacity” to be a party to a lawsuit. However, a person who has been determined to be mentally incompetent due to dementia can still contest a will through a conservator or a guardian ad litem

According to California Code of Civil Procedure 372, adults who lack the legal capacity to make decisions cannot appear in court without a conservator of the estate or guardian ad litem representing them.


A conservatorship is a legal process where the court appoints a responsible person, known as the “conservator,” to make decisions on behalf of an adult who cannot care for themselves or their finances. 

Conservators can be appointed as a conservator of the person, conservator of the estate, or both. A conservator of the person is responsible for taking care of the individual’s personal needs. In contrast, a conservator of the estate handles financial matters, such as paying bills and filing lawsuits. Only the conservator of the estate can represent an incompetent person in a will contest.

Guardians ad Litem

In addition to conservators, a guardian ad litem can also represent a mentally incompetent individual in a will contest. A guardian ad litem is an attorney who is appointed by a court to represent the interests of someone who cannot represent their own interests during a legal proceeding. In a will contest or another legal proceeding, a guardian ad litem can be appointed if the judge determines it will be helpful to the case, whether or not the person is also represented by a guardian or conservator. 

So, for example, if the judge questions whether the appointed conservator is able to act in the best interest of the person with dementia, a guardian ad litem can be appointed to represent them. In these situations, the conservator will still remain part of the case, but the guardian ad litem will also have the opportunity to present the individual’s best case.

No matter the circumstances, the legal proceedings for contesting a will or defending against a will contest are always fact intensive and challenging. You should immediately consult with an experienced California probate litigation attorney in any situation involving dementia and will contests. 

Have questions? We’re happy to discuss.
Call (424) 320-9444 or email [email protected]

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About RMO, LLP

RMO LLP provides personal and efficient inheritance dispute services to individual and institutional clients. The firm’s attorneys focus on probate litigation involving contested trust, estate, probate, and conservatorship matters. Serving California and Texas, with offices in Los Angeles, Pasadena, Orange County, San Diego, Fresno, the Bay Area, Dallas, and Houston. For more information, please visit

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About the Author

Scott Rahn, Founding Partner

Scott Rahn resolves contests, disputes and litigation related to trusts, estates and conservatorships, creating a welcome peace of mind for clients. He represents heirs, beneficiaries, trustees and executors. He utilizes his experience to develop and implement strategies that swiftly and efficiently address the financial issues, fiduciary duties and emotional complexities underlying trust contests, estates conflicts and probate litigation.

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