If he would have been a tiny bit more open about it, I would argue that they shouldn’t fire him. If he had done a few more preliminary steps to make his process a little more transparent, I’d say he deserves a raise.
He performed many duties that other developers couldn’t; quality control, management, keeping a tight timeline, not to mention… “even being hailed the best developer in the building: his code was clean, well-written, and submitted in a timely fashion.”
Innovators commonly look stupid or crazy in the beginning. I give him thumbs up (if only he was a little more open).