I have to agree that he should press for a refund. And if he doesn't get one I would file a DOT complaint or a dispute. He paid for an earlier flight and their computer system reversed that change (doesn't really matter the reason).
It would be one thing if the flight had been DELAYED past the original flight's departure. He might still be livid but the argument could be made that he paid for a particular flight, not time. In this case, he paid to be moved to an earlier flight and they moved him back against his will!