Tennessee still has to release him. He can officially request it, but you better believe that Steele will be meeting with him and attempting to change his mind.
However, if he still wants to leave, then Steele should honor that. Steele needs to be seen as a players' coach who cares about the kids first.
And that is a great point that it is possible that Brooks was offered improper benefits as well. It seems like every high level recruit of the past 2-3 years is jumping ship, which worries me that they all may have gotten a little something something (Crouch, Gray, Toots, Morris). I'm not saying they did, but it wouldn't surprise me.