Kind of doubtful. Amazing he was rerouted on another airline- award tickets are technically only valid on AA. Must have been a pretty tight situation for them to rebook him on DL. Did he ask them to do this or was it involuntary? If it was "involuntary", you may have a point to make with AA-- the big question becomes why wasn't he rerouted on AA in F? Unfortunately,free ticket awards can be used for oneway or roundtrip travel, therefore so as far as AA is concerned he got oneway F on AA. Don't mean to discourage you, but wouldn't count on much. I'd (nicely) ask for half the difference (7,500) as a goodwill gesture, but only if it's clear this was "involuntary".