I think Trump flipped Biden long ago. I think Biden was offered immunity for himself and for his family. In return, Biden was to act as a custodian to the office of the President, and also to frustrate the plans of the neofascists. His job is to stay in the Oval Office (for now) - and not do anything. From time to time, Trump or one of the people in the military are going to ask Biden to do something - Biden is to obey, no questions asked.