He won’t be fired, he will quit. Firing a postal worker is damn near impossible. However, his superiors can, and probably will, make life miserable for him to the point where he quits. Years ago, a female postal worker was fired for not doing her job. She sued to get her job back and won. Management, for the first time, made her do the work required of a postal worker, including the unloading of mail bags from a truck, which can weigh over 100lbs. She was never asked to do that before. She quit rather than try to unload the truck.
Yea I can see his life at the PO will get difficult..I also can see them giving him bad references, not so much what they say but do not say...Like oh yes so-in-so he’s well known in HR..or give a reference in a tone of voice....seen both happen like that.