my guess as both a former teacher and a gamer is that what he really craves is an outlet for his competitive instincts/urge, as most boys do. Schools heavily de-emphasize and even discourage feelings of competitiveness around academic achievement, and that I think is one of the primary de-motivating factors that causes boys to be less interested in school. If there's anything you can do to try to re-ignite, in a healthy way, a competitive aspect to achievement in school, that would allow him to scratch that itch in a possibly more productive way. It seems like the STEM class you refer to possibly already has done that to some extent; being surrounded by other boys with similar interests that probably all want to develop and show off their abilities to contribute has probably ignited some of that passion. Figuring out how to compete with peers in a productive and healthy way is definitely a major part of developing social skills as well.