Someone probably explained to him that if he transfers before he graduates, he would only have eligibility left for the 2016 season to play. Things like that tend to make someone change their mind about leaving. If he was going to transfer he should have done it before he redshirted this year, or after he graduates if he has eligibility left. He'll be eligible to play the 2016 season as a grad student, anywhere. The difference is that staying allows the possibility of playing this season, while leaving guarantees he won't play a single snap this season. Easy decision to me.