As a retired behavioral health provider, , Biden is in the 5 stage grief protocol. HE Currently in anger and bargaining stage. He is out of stage 2 denial. The final stage is acceptance which he is not in as yet. These stages are not necessarily consecutive or independent of each other. So he can be in shock or denial as well as angry. There is no specific time limit, but I am sure he is traumatized by the widespread call for him to retire, which complicates his decision to withdraw.