I think Im in love with my best friends brother?

ok, so me and my friend have been best friends for about 3 years and Im pretty much a part of their family as the "other daughter." Her brother didnt seem like my type at first; moody, dramatic,always has to be right. But after a while he seemed to grow on me (not to mention he has an AWESOME body)haha...and pretty soon I always wanted to be at her house to see him. Theres totally a connection between us and I know he knows that. I think my best friend knows that too which makes it kinda awkward. There have been kind of big hints that he has feelings for me too. My best friend went away to college this year and I havent seen her fam since Saturday to spend the night cuz Sunday her little brother had his superbowl game and we pretty much talked more then me and my best friend and he seemed excited to see me. I know its wrong to like your friends brother but its so hard cuz im like in love with him!! I just dont know what to do...im going to their house in a couple days to just hang out and bring movies over to watch with him and my best friends older sister. Please help!! I dont know if it would ruin me and my best friends relationship or not. I know I love him because Its hard to have relationships with other guys because I think of how much I want to be with him.