Just throwing this out here, as I do regularly:
If I get hit with dementia, just go ahead and kill me. I wouldn't be able to consent at that time, so I'm doing it now.
If I start throwing unrecoverable errors, if I start failing self-tests, take me out of service. It really is that simple.
We all know it won't get better. We all know it will only get worse. We've all watched someone we loved and respected literally turn into an animal that shits themselves and screeches. Go ahead and take me out with The Good Drugs before it gets to that point, please and thank you.