I book a lot of tickets and they are picky when you finalize the deal that the name on the ticket is exactly as the name on the ID.
Years ago I got away with it when I had hubby's nickname in the ticket and given name on the credit card.
Now, I'm not so sure. We have passes to go through TSA faster because we fly a lot and they are sticklers on exact names.
Forget about Expedia at this point. He went through a discounter ( unfortunately) and that limits your customer service. Now its your business to deal with the airlines specifically.
When was the ticket purchased? If within 3 days on a credit card you still should have buyers remorse and then able to go redo it but it could be at a higher airfare and change fee.
If at first you get negative answers from the airline, don't give up. Call back. Many times it depends on the rep you happen to speak with at customer service!!
Good luck!!