I have copies in safekeeping of my parents wills. As I was moving some files around it suddenly occurred to me that their is no provision in the wills for dementia or Alzheimer's disease. My mother has dementia and is in a nursing home (other problems going on with this) and my father is showing his age more and more each day. Either of them could die on any given day so I often find myself playing out those scenarios in my head. To keep her Medicaid assistance she has to have a separate account under her name with less than $2000 dollars in it. She is not capable of making decisions . . . so . . . if my father died tomorrow what would be the most likely outcome? Court appointed guardian?
Another couple, the husband suffered from ALZ. His sister wanted to leave him her estate. NJ law does not allow it, so she left it to the man's wife to be used for his care.
You may just want to consult a lawyer while Dad is able to sign a new one if allowed.
A person with mild dementia can update a Will and POA.
I think you need to get legal advice on this.