BIL called step son gay

My step son is 16 going on 17. He has this best friend who's he's really close to. He lived with him and his mom at one point. He was in the phone with his best friend and they were talking about Dragon Ball Z. My BIL is an ass. I knew him back in High school. He was on the wrestling team and a huge douch and bully to his brother (my husband). My step son got off the phone with his best friend and said "Love you". Bil said "That's fucking gay". Without missing a beat my step son says "So me telling my best friend I love him is gay, but wearing a revealing swim suit looking thing while trying to get on top of guys and hold them down as a sport isn't?" Then said he's going over Michaels house (his best friend). I high fived him. Bil had nothing to say.