At least he knows what he needs to change. If he can come back looser and more aggressive he may be halfway decent. He's just trying way too hard right now. He's playing 1. not to get hurt, and 2. not to lose, and you're not going to be successful that way.
He's a big guy with a big arm and dude's got wheels. It can be a dangerous combination if he learns how to use it. I doubt he'll ever have pinpoint accuracy, but I do think part of his accuracy issues come from aiming his passes.
Plus, dealing with adversity like this will likely help build the kind of character needed to lead men. If he earns the job back rather than having it handed to him he'll earn a lot of respect from his teammates.