This is very curious behavior for sure. I am sure someone can help a little more than me, but here goes...

Does he seem smart? You know Albert Einstein wore the same suit every day, well rather, he had 7 of the same suits. That way he did not have to decide what he was going to wear the next day.

He could have a personality disorder, or maybe mainstream Autistic. That is more of what it sounds like to me that he may possibly have Autistic tendencies.