My grandmother has Alzheimers. She has often been uncharacteristically aggressive towards my mother, grabbing her and pinching her, swearing at her and threatening to throw things at her. A neighbour whose husband developed alzheimers said that one day he grabbed her hair and then started hitting her in a demented rage.
I think under those kinds of circumstances, they should have their guns taken off them if they can no longer be trusted to be rational. My grandmother is still living at home for the time being.
One thing that might work is to keep the guns with the old folks under a combination lock. If they can't remember the number, they can't get to the guns. Of course they still could have enough sense to defend themselves from an intruder, but forget the combo - especially under stress.
Seems like a pretty personal thing, and depends on the people involved. (Sort of like school lunches). Too bad the government and their propaganda arm have to make it a public issue.