Yeah dealing with mental issue is tough, I'm getting concerned with my own Mom more and more.
She used to have an absolutely amazing memory, where give her 5 minutes to remember something and she could repeat it word for word what happened and I couldn't get away with nothing.
Had lunch with my parents today, today she told me something, thought she was telling me some new information. But she couldn't remember that I was the one originally informed her of the information in the first place. It has me nervous.
As far as your grandfather, let him call the police. As soon as they find out he has dementia, they won't want him having a gun either and should back the uncle.
And don't want someone shot just if they're outside, and pose no threat to anyone.
But yes, that's got to be tough for the Uncle and the Grandfather.
