I will tell him, his strongness, and in which subject he was strong.
I will tell about the consequences, and challenges that he will face in his life, if hie doesn't reconsider his choice.
I will talk to his parents, regarding his life, and future, and I will tell the opted group for him, and his nature.
In such a way, I will make him to reconsider his choice.
Hope this will help you.