My father is 77 and has early stages of dementia. My uncle was 80 and died last week and had dementia. My dad has sundowning syndrome. Unlike Biden, he doesn't get better as the evening wears on. Biden was accurately recalling facts the entire debate. My dad couldn't recall a fact told to him five minutes ago. Biden is not quick with the tongue anymore. His speech is slow and lacks energy, however, he still accurately recalled facts and thoughtfully answered the moderators questions. I don't see many people actually saying what Biden said was inaccurate. He then followed that up with a focused and energized rally the next morning. Biden also has a stutter and symptoms of stuttering are freezing and not being able to start words. Bottom line, Biden knows what he's doing. It's weird how everyone says he's in mental decline but don't call on him to resign.
BTW Biden is in excellent physical health. I trust his doctor more than Trump's. Biden bikes daily. Trump is more likely to not make it to election day.