Over Christmas 2005 Hekate used a mind slave spell on him and Skybolt, with the result that they were happy to do whatever they were told by her or anyone she designated, and were used as servants and abused by the Alphas. The spell had to be renewed annually, and Hekate flubbed the renewal by attempting to do Fey at the same time.
It turns out they had been aware of their treatment the whole time. When Cavalier and Skybolt got back to Whateley, they beat up The Don, leaving him in the hospital for most of the Winter 2007 term. They were subsequently sent to ARC for treatment for extensive psychological trauma.
After some special therapy, he was deemed well enough to return to Whateley.