The Capacity Window: Trust Changes After a Dementia Diagnosis
For Families Facing A Dementia Diagnosis · Free PDF Guide
A dementia diagnosis does not lock the estate plan. California law presumes your mom still has capacity, and it measures that capacity on the day she signs, not on the day she was diagnosed. But the window narrows every month, and the families who win later are the ones who built the record now.
A quick, plain-English read. No legalese, and nothing to buy.
From Ridley Law · Eric Ridley · Estate planning, trust administration, and probate
A dementia diagnosis does not automatically end someone’s right to change a trust. The checklist covers what the law requires and how to document it.
What’s inside the guide
- Which trust and estate documents can still be changed after a dementia diagnosis, and which changes get harder to make as the diagnosis progresses
- Why a diagnosis alone does not strip someone of the legal capacity to sign, and what actually determines whether a signature holds up
- How capacity gets measured on the day a document is signed, not on the day of diagnosis
- How to build a record around a signing so a later change is not the first thing a disappointed relative attacks
- Why the window to act narrows over time and what that means for how soon your family should move
Can someone with dementia still change their trust?
A diagnosis by itself does not lock the estate plan. Capacity is not an on-off switch tied to a diagnosis label. It is judged transaction by transaction, and many people diagnosed with dementia retain the capacity to sign trust and estate documents for a period after diagnosis, sometimes a long one. The right question is not whether your mom has dementia. It is whether she understands what she is signing on the day she signs it.
How do courts decide whether someone had capacity when they signed?
The law looks at capacity at the moment of signing, not at the date of a medical diagnosis that may have come months or years earlier. That means the strength of the case for a post-diagnosis trust change rests on what the evidence shows about that specific day, not on the diagnosis itself.
What can a family do to protect a change made after a diagnosis?
Build the record while the window is open rather than after someone challenges it. That generally means documenting the person’s understanding close in time to signing, choosing the right professionals to involve, and not waiting until the diagnosis has advanced to act. The families who avoid a fight later are the ones who did this while there was still time, not the ones who scrambled after a decline.
If the plan itself needs updating rather than just a single change, start with estate planning.
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