I used a 40k award to fly my brother SAV-DFW-SEA as a christmas present. Upon checkin at SAV, he was told of his delayed flight to DFW and missing his flight to SEA. They rerouted him on a DL flight SAV-ATL-SEA where he was ticketed in coach despite open seats at the time of booking in FC.

He was able to fly FC on AA back to SAV. I am wondering, do I have a legitimate gripe in trying to get 7,500 miles back to my account? (the difference between coach and FC didided by 2)