Garliv I don't think Biden is that far gone. He has simple gaffes not lack of comprehension. I wanted Sanders but still Biden any day over Trump.
It's a popular talking point. On the right. The polls currently have Biden with a healthy lead going in. If the worst that can be said about the guy is incoherence, in today's political environment, that seems like a powerful endorsement.
In any case, it makes his pick for veep(we know it's a woman) that more interesting. I see Elizabeth Warren and Kamala Harris as prohibitive favorites, with a Harris pick being more reassuring to conservative undecideds.
I don't think anything any of them does matters at this point. Both sides are dug in, with GOP being that way since 2016. That's why I don't see corona having an impact one way or another.