How do i get my younger brother to stop being ashamed of my gay dad and using him?

im 17 and brother is 16 and he's definently going through the rebelious stage of his life and with our dad suddenly coming out of the closet to us he is just even more of a ticking time bomb around us. my house is divded , my brother and i get along and my father and i get along but they , well my brother does'nt want anything to do with him if it does'nt pays but my dad would die for this ungrateful kid . my dad has always been kinda not so manly but not so flamboyant(sorta like harvey milk) and my mother says she never saw him as a bf but just a gay bestfriend that she thought would be fun to have kids with because he wanted them more than her and she thought he would be the only good father figure for any kids she have because he is indeed so generous and optimistic no matter how hurtful people can be. my brother shecklin ..he's the all american boy , good looking shaggy hair, he's on the track team , and he thinks he's hot stuff , he's a sweetheart to girls only but he's hard on guys especially gay guys. we both live with my dad and it was fine until my brother turned 15 and started to really like girls and hang around moronic guys who think they're all bad boys. Shecklin and my dad and i were close between the ages 1-14 and now he uses my dad , he'll spend time with him only for money , the time is only less than 5 mins and he's always asking for exspensive stuff and my dad just buys it hoping shecklin will come around but after he gets the money or whatever sooner or later it's "go to hell dad!" he slams doors when he enters or leaves, he even accused one of my dad bf's of checking him out so my dad barely dates or have guys over , he puts on a smile for my brother but i cry for him just as i know he does inside. He even jokes sarcastically alot about my dad uality , we had a bbq and my dad was eating a hotdog and my brother started pretending to vomit telling my dad to eat his hotdog away from him because he think it's sick being around gay guys and hotdogs but he's seems so clueless sometimes , so my dad smiles and its all "ok." it hurts me deeply because my dad is a softy when it comes to his children but he has to stand up for himself against my brother. what should i say or do??