Another Hillary?
Hillary was close to death after her campaign. She was constantly sick, fainting, and disorientated.
Politicians have no job. They do not 'work' like you and I do.
When they actually have to 'do' something real, it tears them up.
They're not used to actually 'doing something'.
Could be that Biden will slowly fall apart, one thing after the other, during the campaign, like Hillary did.