Needing Advice: Family Fueding...

Okay so long story short my boyfriends father cheated on his mother with his cousins wife who he considered like a sister to him. Huge divorce and family drama followed! My boyfriend who was 20 when all this went down tried his best to keep a good relationship with both his parents regardless of how angry he was at his dad. Fast forward to now, his fathers family reunion is approaching and my boyfriend called his dad to set rules about him bringing his whore along. (I hate her guts for the record she's done this to families 3 times ...) his father refuses to speak with him alone about it and says that his whore can over hear everything. Then said if my boyfriend wants to talk then he can talk infront of her at the reunion ! Mind you he lied to everyone about how they met so only me and my boyfriend know the story ... It's pretty shitty... But now my boyfriend is beyond hurt and pissed at his dad for not even hearing him out. All he wanted was for her not to be included in the family pictures! How can I help!? I literally want to call his father and ask him if his whore is really more important then his son... Idk what to do...