I'm convinced the guy living with me is santa claus
Are you joking? Why do you believe this?
Yes, it's an opinion, not a fact.
It is not a rational thing to believe you know Santa Claus. It is best that you understand Santa is not real.
We should call Santa Claus, he knows how to get on the north pole.
Santa clause is old Norse folk lore, medicine man feeding mushrooms to reindeer tripping in the forest. There is no fat man in a red suit living at the north pole bringing kids presents.