I'm going way out on a limb here.... You mentioned that he is very literal. This struck a chord with me because of a friend's child who went thru pure hell until he was determined to have Asperger's syndrome.  Taking the world very literally is one of the hallmarks of Asperger's, along with many other signs. It might be something to look into. It's so hard to see the little guys struggle and we all want to make it easier for them.