One strategy to try is to have him puts books that need to go home on a particular shelf throughout the day in his locker. Then at the end of the day, he empties that shelf into his backpack to go home. Or, he can turn the binding of the books to go home toward the back of the locker and then grab those at the end of the day. If either of those strategies do not work, some students just do best by bringing home each book every night.