Just gonna point this out, Rei. I may redline later if I have the time.

The boy has some very flat shoulders. He needs more downward slope in them for them to act more like the human bodies does. Also, with that change made, you'd also need to bring down the angle of the collar bone. His neck also looks really old due to the boldness of the lines for the clavicle(? Sorry, really tired at the moment.). I'll probably redline him when I get some time (After I sleep most likely.) and figure out anything else that is wrong with him.