I went through a small version of this. My father-in-law had Alzheimer's and was able to cover for some years by mostly answering questions by asking questions

I went through a small version of this. My father-in-law had Alzheimer's and was able to cover for some years by mostly answering questions by asking questions. Locks appeared on the property, and started moving daily, if not sometimes hourly (different keys, combinations, etc.) I invested pretty early in a good set of bolt cutters. I learned quickly to start any approach and conversation with "Hey, dad" otherwise he would seem to decide I was a stranger up to no good and try to run me off the property. He would have moments of lucidity where he would admit he was terrified, that he was pretty sure he was losing his mind. But they were pretty fleeting. I remember one night he kicked my mother-in-law out of their house, claiming he was going to kill anyone who came in. The Sheriff was called and it was mentioned that not only was he a Korean war vet, he had guns in the house. That was the night SWAT stayed outside our houses (we live next door) until morning, as my father-in-law hung up on the Sheriff's Deputies and refused to answer any subsequent door knock or telephone call. Early that morning it was surreal to see the SWAT team serpentining across our lawn, guns drawn. My father-in-law answered the door, invited the Deputies in for coffee, was confused when they took him into custody, then handed me his keys saying he didn't know what he did, but apparently he was in trouble and I better watch over the place. Turned out he had a toothache no one was aware of and was having a hard time coping with the pain, since he couldn't stay focused long enough to tell anyone about it. Luckily, no one was hurt over that whole period and my wife got to spend the last year and a half with her father before he died of cancer and complications from Alzheimer's. It has also resulted in some long talks with my wife about how long either of us wants to be kept alive, in the result of not being mentally with it, or mentally awake in a failing body. We learned quite a bit about Power of Attorney and Medical Directives, as well.