He might be on the spectrum. People who are are prone to obsessive thinking and don't always have a filter when it comes to their special interests. I know I would drive other folks crazy if I was talking about mine, but some folks either can't help it or haven't gotten the counseling they need to help them do so.
I guess he could also just be a neurotypical person who has nothing else going on in his life.
God forbid you ever had to walk a mile in her shoes, 'cause then you really might know what it's like to have to choose. - Everlast