I am in agreement also on this. It would drive me crazy if this happened. But unless your son took pictures of before and after not much can be done. You say (to the OP) that he does have a cover for it. Well, then just put it back on.
But there is no excuse for it to have scratches on it especially if it’s a lot of them. They should be using soft cloths to put the electronics on when working on them. But crap does happen. As suggested there are protective skins (different colors) you can get to fully protect the computer. Maybe suggest he gets one or gift him one that he picks out.
I am pretty anal when it comes to stuff like this. So I get it. He should write a complaint to the person in charge and this might be good for him to do anyway. But then move on especially if it’s student driven It. At a larger store like Apple they would just replace the outer cover if they could.
But there are all sorts of cool skins you can get and lots of students use them.