Joe Biden showed the world he isn't too old. And Donald Trump showed the world he is.
Trump is absolutely too old... but so is Biden. The man has barely been able to form coherent sentences consistently for over a decade now. I certainly dont want Trump to win, but we have to stop fooling ourselves that Biden isnt senile, he very clearly is. Our only real hope is if we get someone nominated other than Biden or Trump as a front runner. The best (only) thing the democratic party could do at this point (but wont) is not endorse Biden.
Momentary flashed of coherence is the best you can accept from either the current president or the last.