I was just thinking it over today...he literally said during the campaign that if things get bad enough then he'll just fake some type of debilitating disease and let Kamala finish the term.
But, that's only if he initiates it. If his handlers' patience grows thins they'll make him a martyr and set up an assassination. They'll even have some Richard Jewell type, someone that they can paint as a redneck racist cracker gun nut that they can pin it on. That'll be a win/win for them.
Anyhow, just my prediction.