Because President Biden is 80 years old, there are many who choose to believe he’s knocking on death’s door and could die unexpectedly any day now. That’s true for any of us, but I won’t pretend that it’s not more probable the older you get.
It doesn’t matter how well he does his job.
In some people’s minds, in the not so distant future, he won’t be able to do his job properly anymore even though he does not have any form of dementia.
All old people do not have, or get, dementia. It is not a normal part of aging contrary to popular belief.