“Severe dementia” is far different than the old person behavior that Biden occasionally exhibits, which is like, saying the wrong word once or twice while speaking for half an hour. The “he doesn’t know what room he’s in!!1!” claims are absurd. When you listen to him talk for a while he’s perfectly coherent, though people like to cherry pick 1-2 lines out of context to try to pretend he’s doddering and incoherent.