if you wanna get to the bottom of this guy I suggest you check out the work of Dr. Paul Ekman. he is the foremost authority on facial expressions in relation to emotion:
http://www.paulekman.com/
there are 7 universal facial expressions, and thousands of learned cultural expressions. According to Ekman even people who have learned to control thier emotions, still "leak" clues to what they are feeling through subtle expressions known as micro expressions. I guarantee this guy is exhibiting mirco expressions, you just need to learn to read them.
but keep in mind that you might learn to recognize a subtle emotion on his face, but there is still no way to read what that emotion pertains to or who it might be directed at. for that you need to be able to ask the right questions and get him to open up.