If he's one of those big, muscular black guys I'm pretty sure they won't say anything..at least not whilst he's there standing in front of them. But seriously..just set them straight dude.
Before he even arrives you should have a word with them about it and if they start getting racist whilst he's there you need to slap their face left to right. For real, or he can bring some of his dons along with him and see what they have to say then..like ew man, your family is disgusting.