Dementia. It can suddenly push forward, fast. To where the person is now gone, a shell of their former selves. Then it can push onward even to death.
If Biden were to be re-elected he might not make a full term, and rhen we are facing his Vice President is President.
I loathe Joe and Jill. It would suit me fine if he spent his last five years of life not remembering her name, and making lewd comments while grabbing at her while she changes his diapers. Not that I think she’d hang around for it. Probably be in the Caribbean, boffing cabana boys.