I think my brothers best friends is gay but im not sure?

Ok my brothers best friend lives with us and he is always hanging out with my brother. I mean all the time i dont think there is a time when there not hanging out. He is always wanting to fight him but not like really fight like play fight. We all have been hanging out for the past week we evan sleep in the same room last night and the night befor. But i sleep in the floor and they sleep in the bed together. I dont think that would make him gay but ive seen stuff that does. Like i seen him rub his legs and he evan kissed him on the cheek. He said he was just kidding but i dont beleive him. My brother pulls away from him when he starts to rub his legs or trys to get really close. I know my brother isnt gay cause he has a girlfriend and he is always kissing her and her when he can. I dont care if he my brothers best friend is gay i would just like to know cause then i would know not to hit on him or flirt with him. He is really cute and he likes me but i still think he likes guys just cause the way he acts around my brother. So if anyone can help plzz do. Do not think i dont like gays.