there is nowhere else they can appeal. They have to accept it as a final arbitration.
The award, notified by the CAS Court Office, shall be final and binding upon the
parties. It may not be challenged by way of an action for setting aside to the extent that
the parties have no domicile, habitual residence, or business establishment in
Switzerland and that they have expressly excluded all setting aside proceedings in the
arbitration agreement or in an agreement entered into subsequently, in particular at the
outset of the arbitration.
What else can they do, they cant refuse him wild cards now he has no hearings pending and tournament draws are random. I can't see they can do anything else.