She is physically frail, but she is 85 years old.. those trying to claim she is mentally unstable are just partisan hacks. I do not care for her, but she is not mentally deficient in any way.
She had plenty of time to retire, and since she has not, she’s probably going to die in office, but at present she is not mentally deficient..
If I were her age, and on my way out sooner than later, I'd be retiring and spending what few years I have left with friends and family and unwinding from a long career.