1. Bidens predatory problems were known long before now.
2. Why not dump him for health reasons? It would be much easier and even generate some sympathy from voters.
I totally agree. Announcing he has a serious health issue that would prevent him from running would give them a perfect out. His primary voters would not question the decision as it would have "just come to light" so would still vote for the eventual nominee. There would be universal sympathy for him- especially if they announce something like Alzheimers.