A List of Cages - Robin Roe

When Adam Blake lands the best elective ever in his senior year, serving as an aide to the school psychologist, he thinks he's got it made. Sure, it means a lot of sitting around, which isn't easy for a guy with ADHD, but he can't complain, since he gets to spend the period texting all his friends. Then the doctor asks him to track down the troubled freshman who keeps dodging her, and Adam discovers that the boy is Julian - the foster brother he hasn't seen in five years...