Contesting a Will Due to Dementia

Emily’s son, Mac, discovered a new will after her passing that completely disinherited him. He was shocked. Emily, in her late 80s, had suffered from increasing memory loss for years. The will, dated just six months before her death, left everything to a new “friend” Emily barely knew. Mac spent $25,000 in legal fees trying to prove the will was invalid, only to find out he lacked the necessary evidence to overcome the presumption of its validity. He lost, and the friend inherited everything. This scenario happens far too often.

As an Estate Planning Attorney and CPA with over 35 years of experience, I’ve seen countless wills challenged based on concerns about the testator’s mental capacity. It’s a painful process, but a necessary one if you genuinely believe the will doesn’t reflect your loved one’s true intentions. The key is understanding what California law requires to successfully contest a will, and realistically assessing your chances.

What does it take to prove a will is invalid due to dementia?

The standard isn’t whether Emily had dementia, but whether she had the capacity to understand what she was doing when she signed the will. This is a subtle but crucial distinction. California uses a surprisingly low threshold for capacity. Under Probate Code § 6100.5, a person is considered of ‘sound mind’ unless they lacked the ability to understand the nature of the testamentary act, the nature of their property, or their relationship to living family members (or suffered from a specific delusion).

This means that even someone diagnosed with early-stage dementia can still have the capacity to sign a valid will. The focus is on their state of mind at the time of signing. Medical records documenting a general decline are helpful, but aren’t enough. We need evidence showing Emily specifically lacked understanding on that day.

What kind of evidence is needed to challenge the will?

Strong evidence is paramount. A doctor’s note stating, “Emily had dementia” won’t suffice. We’re looking for things like:

• Witness Testimony: Statements from people who observed Emily around the time of the signing. Did she seem confused? Disoriented? Unable to recall recent events?
• Medical Evaluations: A neuropsychological evaluation conducted near the signing date is gold. These tests assess cognitive function and can provide objective evidence of impairment.
• Emily’s Own Statements: Did she express concerns about her memory or understanding to anyone?
• Changes in Behavior: Significant and unusual changes in Emily’s behavior leading up to the signing.

The more contemporaneous evidence (meaning evidence created at the time of the signing) you can gather, the better. Hindsight bias – recollections after the fact – are less persuasive.

How important is the timing of the medical evaluations?

Critically important. A medical evaluation from a year before the signing carries less weight than one from a month before. We need to demonstrate Emily’s capacity was compromised when the will was executed. If the will was signed shortly after a lucid interval (a period where her dementia symptoms temporarily subsided), the challenge becomes much harder.

Can a caregiver’s testimony be used against the will?

Potentially, but it’s complicated. If the caregiver was involved in drafting or procuring the will, Probate Code § 21380 comes into play. California law presumes undue influence if a gift is made to a care custodian of a dependent adult. The burden then shifts to the caregiver to prove they did not coerce Emily. This is a high hurdle, and we often see cases where the caregiver is disinherited and liable for attorney fees. However, simply being the caregiver isn’t enough; we must show they exerted influence over Emily.

What happens if I can’t gather enough evidence?

This is a tough conversation, but a necessary one. Contesting a will is expensive and emotionally draining. Before filing a lawsuit, we thoroughly evaluate the evidence. If the chances of success are low, pursuing the challenge could deplete your resources and cause further heartache. As a CPA, I can also help you analyze the tax implications of a successful – or unsuccessful – challenge. The step-up in basis and potential capital gains need to be carefully considered. A poorly planned contest can have significant financial consequences.

What determines whether a California probate estate closes smoothly or turns into litigation?

California probate is designed to provide court-supervised transfer of property, yet cases often break down when authority is unclear, required steps are missed, or disputes arise over assets, notice, and fiduciary conduct. When the process is misunderstood, families can face avoidable delay, escalating conflict, and increased exposure to creditor issues, hearings, or litigation before the estate can close.

• Court Dates: Prepare for the court hearing in probate.
• Steps: Follow strict procedural considerations.
• Tracking: Maintain case management logs.

A stable probate administration outcome usually follows from clarity, consistency, and readiness for court review, especially when multiple stakeholders and competing interpretations are involved. When documentation supports enforcement and timelines are respected, families are less likely to face preventable escalation.

Verified Authority on California Will Contests

• The 120-Day Statute of Limitations: California Probate Code § 8270
  Time is the enemy in a will contest. Under Section 8270, an interested person may petition the court to revoke the probate of a will, but this petition MUST be filed within 120 days after the will is admitted. Missing this deadline is usually fatal to the case.
• Mental Competency Standard: California Probate Code § 6100.5 (Unsound Mind)
  This statute defines exactly what “mental incompetency” means in probate. It is not just general forgetfulness; the contestant must prove the deceased did not understand the nature of the testamentary act, could not recollect their property, or was suffering from a specific hallucination or delusion that dictated the will’s terms.
• Presumption of Undue Influence (Caregivers): California Probate Code § 21380
  To protect vulnerable seniors, California law automatically presumes undue influence if a will leaves assets to a paid care custodian or the lawyer who drafted the instrument. This shifts the heavy burden of proof onto the accused to prove their innocence.
• No-Contest Clause Enforceability: California Probate Code § 21311
  Many wills contain threats to disinherit anyone who challenges them. This statute limits the power of those clauses. A beneficiary cannot be penalized for a contest if the court finds they had “probable cause” to file the lawsuit.
• Standing to Contest: California Probate Code § 48 (Interested Person)
  Not everyone can sue. To contest a will, you must qualify as an “interested person”—typically an heir who would inherit under intestate succession (if there were no will) or a beneficiary named in a prior valid will.
• Financial Elder Abuse Remedies: California Probate Code § 859 (Double Damages)
  Will contests often overlap with elder abuse claims. If the court finds that a person used undue influence, fraud, or bad faith to take assets (or change a will) to the detriment of the estate, they can be liable for twice the value of the property taken, plus attorney fees.