For the first time ever (that’s over 26 years), a jacket was taken in error from our office closet. Apparently a nearly identical jacket was left behind, but it wasn’t the person’s jacket. Somehow the receptionist remembered who she thought wore the jacket and was able to arrange for the switch back by calling and asking about it. The next week I hung my coat in the closet at the hairdresser and when I saw how many black jackets there were in there, I got nervous myself about a potential for a mistake. (I leave my blouse in the jacket when I change into a robe at the hairdresser, so if they take my jacket they get my blouse too!) I would hope it was just a mistake somehow, but I do believe it possible that people could take a nice coat.
It sounds like the OP’s son has some good ideas for how to replace his lost coat. Maybe one of his friends has a spare coat or jacket to loan him until he can get a replacement?