OCD
I have a friend that refuses to let anybody sit on his bed unless it is on top of his comforter and he'll pretty much attack you if you come near his pillow.
He also makes a toilet paper net in the water before he drops a load to prevent any possible splashback. Of course he puts more toilet paper on the seat even when he's only sharing the bathroom with his roommates.
Is that germaphobia normal?
Either way, it's his problem, not yours. Don't worry too much about it.