Please see my related comment #39.
As you may recall JFK relied on powerful pain meds. I think we’re seeing something similar with Biden only its not about physical pain.
He is missing a part of his brain, most forget- from prior brain surgery, and not too bright to begin with always full of brag about his grades in school, graduating place in class, and so forth. He had to quit a Presidential run over his lying and arrogance about his own “brilliance”.
So for some time, he has been on all kinds of shall we say ‘elevating” agents, stimulants, narcotics— and we should not forget the jet black contact lenses he wore at debates (he has blue eyes- his eyes were jet black (tech people have explained what these were- so he could be fed info to read live, and in secret from any observers. Didn’t work).