It sounds like the two of you could use a relaxation routine for him when he gets home from school. I know one kid who was having similar issues, although not so much crying but some crying, whining, falling apart, etc. So her dad got her a whole bunch of books on tape and when she gets home from school, she gets a snack plate and lies on the rug in the living room having a snack and listening to a book on tape. This relaxes her and helps give her more energy used during the school day. Then she has a much easier time dealing with the rest of the afternoon/evening.