To answer the question in the title of the thread: we do not know what his problem is or what his problems are, nor is it at all relevant. Your problem is that, in your words, "Why do I sit here upset over something clearly so not good for me?"

That problem should be dealt with and since you own this problem, you are capable of dealing with it.

You are by and large not capable of dealing with his problems even if you are successful in determining what they are, so the time spent on finding out what they are will be for the most part wasted.