I'm in love with my brothers bestfriend?

no way is it wrong, but he might just be luring you into one of his traps if he really is a player. if you guys hang out alot, observe him, does he look at other girls or talk about them? if not, then maybe he really is into you...but dont be surprised. your best girl warned you already that hes a player and she didnt even know you liked him. so..be careful, but dont be scared to have feelings for him.