I think one of two things are true.Anyone with experience of someone with Dementia with access to stimulants/drugs that could prop them up? How does Biden's handlers hope to have him standing on his own Vs Trump on live TV?
He cant even do a morning interview with canned questions.
#1) The Democrats will replace Biden before the debates.
#2) The Democrats don't care about 2020 because they know the demographics mean they will run this country top to bottom in 2024. So they are punting on this election. They are not running Bernie because they don't want a candidate that actually offers the working class anything. And they don't want their younger candidates to get exposed by Trump and Trump's base. They will save their powder for a better day.