He is certainly showing signs of some sort of mental impairment.... as is Donald Trump, entirely expected as you go into one 80s.
Trump rambles, forgets where he is, who he is talking too, former aides of his, say that he is insane.
At least Biden had the insight into his condition to withdraw, Trump still thinks he is perfectly ok.
Which is why we need Harris in charge, not Trump, who would certainly be succeeded by Vance, who is appears to be very extreme in his views, is that get get elected? who knows? but its not a chance the US should take.