The meds no longer work. But if his handlers up the dose Dementiajoe could vaporlock or blow a head gasket.
Agreed - they have run out the string on "better living through chemistry" while also re-calibrating Biden's circadian rhythm and his mainspring is now well past its max torque value. Assuming a clear Trump victory with minimal electoral hi-jinks, I think it's unlikely Biden has any gas left in the tank for any sort of concession appearance.