What If a Will or Trust Was Changed When Someone Lacked Capacity?

Q: What If a Will or Trust Was Changed When Someone Lacked Capacity?

A will or trust made without mental capacity is invalid under Arizona law. A person must understand their property, heirs, and the effect of signing. If dementia, illness, or confusion impaired judgment, the court can void the changes. Berk Law Group’s Scottsdale attorneys handle capacity and undue influence challenges throughout Arizona.

Capacity Is the Foundation of Every Valid Estate Plan

For a will or trust to be legally valid in Arizona, the person who made it (the testator or settlor) must have had sufficient mental capacity. If they didn’t — for example, because of dementia, Alzheimer’s disease, medication effects, or delusions — the document, or its amendments, can be declared invalid.

These cases often arise when someone changes their estate plan late in life, under questionable circumstances.

Legal Standard for Testamentary Capacity in Arizona

Under Arizona law, a person has the capacity to make or change a will if they have the ability to:

Understand the nature and extent of their property,
Recognize the “natural objects of their bounty” (i.e., family and loved ones), and
Comprehend that they are signing a document to distribute property at death and understand it’s effects – who will get what.

If a person meets those elements, even with mild cognitive decline, they may still have testamentary capacity. The same standard generally applies to will substitutes, like trusts or non-probate transfers like beneficiary deeds, payable on death accounts or other beneficiary designations.

When a Lack of Capacity Invalidates a Will or Trust

A lack of capacity may render a document invalid if:

The person did not understand what they were signing,
They were confused about their property or heirs,
They suffered from hallucinations or delusions that influenced their decisions, or
They were under medication or mental illness impairing judgment.

If proven, the will or trust (or just the affected portions) can be set aside by the court.

Warning Signs of Incapacity

Indicators that someone lacked capacity at the time of signing include:

Diagnosed dementia or cognitive decline
Confusion about relationships or finances
Inconsistent or irrational changes to the estate plan
Medical or caregiver notes showing memory loss or disorientation
Statements from witnesses or attorneys about the person’s confusion

Such evidence can help establish incapacity in court and may warrant further investigation.

Interaction with Undue Influence

Capacity and undue influence often overlap. Even if a person technically had capacity, the weaker their mental state, the easier it may be for someone to manipulate or coerce them into making changes they wouldn’t otherwise make. Courts look at both factors together to determine true intent. Or whether someone was unduly influenced or defrauded into signing the document.

At Berk Law Group, We Investigate Capacity and Protect True Intent

If you believe a will or trust was changed when your loved one lacked capacity, our Scottsdale probate and trust litigation attorneys can help. We analyze medical, legal, and testimonial evidence to reveal what really happened — and ensure Arizona law protects your family’s rights. Contact us today for a confidential consultation.

Watch this video to learn more about testamentary capacity in Arizona.