Supports racism but not incest ?

My boyfriend and I both live with his parents at the moment and his sister just announced that she’s pregnant , my boyfriends parents congratulated her while questioning her about the child’s father at the same time ( the father is her cousin ) after asking a couple of questions the dad says well as long as you’re not dating a black man it’s okay.... I’m honestly disgusted as a black women and as somebody who wanted to join this family one day. ( I should also add that my boyfriend hasn’t been talking to his mother or father since the comments were made, and he hasn’t spoken to the sister in years since she and the cousin started dating ...he’s angry, hurt and embarrassed)