I am hoping someone with experience getting involuntarily bumped on an award ticket might be able to help.

My son was flying BOS-DEN, DEN-ASE yesterday on a Standard award ticket (50k). He was involuntarily bumped from the DEN-ASE flight because of a weight restriction, and the next flight available to ASE was the following morning (his flight was early afternoon originally). UA would not pay for meals or hotel, though they offered to get him on a bus at his (my) expense ($100). They also offered a free round trip ticket, which he tried to decline in favor of compensation for the missed flight and hotel/food, but they refused. He took the round trip ticket, but we are unlikely to be able to use it because, as I understand it, it has the same restrictions as a Saver award. He is 18 and I just wanted him to get there, so he paid the $100 and got to ASE about 7 hours late.

Given that he was bumped involuntarily it seems like UA should either have paid for his hotel and food overnight, or his bus fare. Is there any legal basis for claiming this from them, and is he entitled to get a refund of any sort (miles or cash) for the portion of the transportation (DEN-ASE) that UA didn't provide?

I know involuntary bump compensation is supposed to apply on the basis of the fare paid, but I'm not sure what that means when the fare was miles not dollars...