From the sounds of things, it sounds like Alzheimers. My family has dealt with it for three family members, and the breaking point for needing around the clock care has always been going outside in the nude.
My great-grandmother and grandmother also had the same affliction, and that was when they were admitted. Both women, as sweet as can be, had a dramatic change in personality once the disease progressed far enough. My grandmother would get occasionally violent, even with me, for trying to help her. I had on more than one occasion restrain her from hurting me, such as trying to bite me.
On that note, any cop who tazes an 80 year old woman and cannot disarm her without resorting to that method needs a new backbone and a new set because what they have certainly doesn't work.
What's next, beating down mentally incompetents? Oh, right. That already happened in CA where the homeless man died from the beating.
