Herpeset Review
He really does not realize that he is sending out the wrong signals when he displays a certain behavior. He may fall head over heels in attendance but not mean anything more than a neat friendship and nothing else. So you have to be wary before jumping to conclusions.
Your guy may just have drifted into a deep thinking mode and nothing more. But this thinking mode has made him withdraw into a cocoon that is impenetrable by you or anyone else for that matter. Find an appropriate moment to ask about his problem.