What's a word to describe a student who goes out of his own way to help others succeed? I'm trying to describe someone who often helps others with their work before doing his own and patiently explains concepts to someone who is confused during a lecture, just to give some examples.
I'm not looking for general words like team player, helpful, or kind; I'm trying to find more specific terms like didactic or cooperative. But I need a word that has much more of a positive connotation than cooperative.