Highlights:
- In California, you can contest a trust within 120 days of notice under Probate Code § 17200 if it was changed during a parent’s cognitive decline.
- To prove lack of capacity, show your parent didn’t understand the act, their assets, or family ties at the time of the trust change.
- Undue influence includes isolation, manipulation, or late-life changes benefiting someone in control; courts may shift the burden of proof if red flags exist.
- Disinherited children and caregivers may have standing to challenge a trust, especially with evidence like medical records, old trust versions, and witness statements.
When a parent with late-stage dementia rewrites their trust and disinherits their only child, it raises immediate legal and ethical concerns. Trusts are powerful tools, but they are not immune to abuse, especially when cognitive decline is involved.
If you cared for your parent, lived in their home, and expected to be part of their estate plan, only to be suddenly cut out in favor of someone else, you may have legal grounds to act. California law does allow you to challenge that kind of trust. But the window is narrow, and the burden to prove mental incapacity or undue influence can be high.
Can A Trust Be Contested After The Settlor Dies?
Yes, it can. In California, a trust can be challenged after the settlor, the person who created the trust, has passed away. This is often when the full scope of the changes comes to light. If you’re an heir who was excluded or replaced, this is your legal moment to act.
Under Probate Code § 17200, you must file your contest within 120 days of receiving formal notice that the trust is being administered. This short timeframe is strict. Miss it, and the court may bar your claim, no matter how unjust the situation feels.
Courts will examine whether the settlor had capacity, whether the trust was the result of undue influence, and whether any part of the document reflects fraud or coercion. These are your pillars in a trust contest. The fact that you are an only child, lived in the house, and gave up years to provide care absolutely matters, but you’ll still need legal grounds to proceed.
How California Defines Mental Capacity To Change A Trust
Not all memory loss invalidates a legal document. But California courts take cognitive decline seriously, especially when someone with dementia rewrites a trust in a way that harms close family members.
What The Law Says About Capacity
Under California Probate Code § 6100.5, a person must understand three key things to have the mental capacity to create or amend a trust:
- The nature of the act: that they are changing their estate plan.
- The nature and extent of their property.
- The relationships to those affected by the trust. For example, child, grandchild, caregiver.
Dementia can impair all of these areas. Courts look beyond the diagnosis, asking whether the person could still make rational decisions at the time the trust was changed.
What Judges Look For
- Medical records noting confusion, memory loss, or disorientation.
- Inability to recognize long-standing relationships.
- Changes made after a dementia diagnosis or while under heavy medication.
- Inconsistent statements or irrational fears, such as claiming their child is “stealing” without evidence.
- Prior versions of the trust that shows a completely different intent.
Judges also weigh your role in your parent’s life. If you were providing day-to-day care while someone else arranged a trust change in secret, that’s a serious red flag.
What Counts As Undue Influence In A Trust Change
Undue influence doesn’t always look like coercion in a movie. In real life, it can be subtle, someone taking control while isolating an aging parent, whispering that their child is ungrateful, or slowly rewriting the story of who deserves what. California law recognizes this manipulation and allows courts to undo trust changes caused by it.
Under Welfare and Institutions Code § 15610.70, undue influence is defined as excessive persuasion that overcomes a person’s free will and results in unfair outcomes. It often involves a confidential relationship, where the influencer has access, trust, and control.
The court watches for these signs:
- The person who benefited helped draft or arranged the trust change.
- The new trust disinherits close family without explanation.
- The trust-maker was dependent on the new beneficiary (physically, emotionally, or financially).
- The change occurred late in life, after medical or cognitive decline.
- The trust-maker was isolated or cut off from other family members.
If a person in a position of trust, like a caregiver, sibling, or friend, arranged the trust change and benefited from it, the court may shift the burden to them to prove the change was legitimate. That’s a powerful legal advantage, and one many disinherited children overlook.
What Evidence Helps Prove The Trust Was Invalid?
Having legal standing is one thing; proving your claim is another. In trust contests involving dementia or undue influence, evidence is everything. The court needs a clear picture of your parents’ health, relationships, and intent around the time the trust was changed.
Let’s break down the most effective forms of evidence and what each one shows.
| Type Of Evidence | What It Proves |
| Medical Records | Confirms dementia diagnosis, cognitive decline, and medication use |
| Old vs. New Trusts | Shows how beneficiaries were added or removed without a clear reason |
| Caregiver Testimony | Establishes your role and any isolation or pressure you witnessed |
| Emails or Texts | May reveal manipulation, secrecy, or attempts to rewrite history |
| Calendar or Timeline | Connects the timing of the decline with the trust amendment |
| Witness Statements | Supports that the trust-maker did not understand or approve the changes |
You don’t need all of these. But the more layers you can present, medical, testimonial, documentary, the stronger your claim. Courts are hesitant to overturn trusts without compelling, credible evidence. Focus on facts over feelings, and timelines over assumptions.
Do You Have Rights As A Disinherited Child Or Caregiver?
You may have more rights than you’ve been told. Just because you’re not named in the final version of the trust doesn’t mean the court will ignore your claim. In California, trust law allows disinherited heirs, especially those who provided care or lived in the home, to challenge a trust under specific legal theories.
Standing As A Disinherited Child
Children are not automatically entitled to inherit if a parent creates a valid trust. But if you were a beneficiary in prior versions of the trust, or the new trust excludes you without explanation during your parent’s cognitive decline, then you may have grounds to file a trust contest under Probate Code § 17200.
Also, if your mother did not understand that she had a child or was manipulated into believing you had abandoned her, that can be critical to showing incapacity or undue influence.
Caregiver Status & Equitable Claims
You moved back, cared for your mother for years, and lived in the home. That matters.
While caregiving alone doesn’t entitle you to inherit, courts can consider:
- Equitable estoppel (you relied on a promise of support).
- Resulting trusts (you helped maintain or improve the home).
- Probate Code § 850 claims if assets were wrongfully transferred.
The fact that you are also disabled may open doors to low-income protections and even emergency housing relief, depending on your county.
Your Voice Matters In Questionable Trust Changes
If your parent changed their trust late in life, while battling dementia, and left everything to someone else, trust your instincts. Courts don’t expect you to be a lawyer, but they do expect you to speak up if something looks unjust. You don’t have to accept being erased from your own family’s legacy, especially after years of sacrifice and caregiving.
At San Diego Civil Litigation Lawyers, we help people like you, disinherited children, overwhelmed caregivers, and rightful heirs, stand up to questionable trust changes. Whether you’re facing a manipulative relative or a silent document that doesn’t match who your parent really was, we’re here to help you challenge it. You’ve already done the hard part by showing up. Let us help you take the next step.
