D.B.
It's frustrating and unacceptable, but I think the uncle is beyond your reach.
I also think that reaching out to the child's father is going to be fruitless. Why do I say that? Because he has no regard for the mom or her feelings anyway, because the mom is doing all of the work with shuttling the child for meager visitation with a disinterested father. This is the most unequal parenting program I've seen in a long time. There's no way the mom should be doing this! If the dad wants to see his child, he needs to show up at the child's door at lot more often, and not make the mom jump through so many hoops. If there's an occasional situation where it's more convenient to pick the child up at an activity, fine. If Grandma has to help out now and then and Mom doesn't want to inconvenience Grandma, maybe it's okay to help out. But this intense scheduling of the custodial parent (Mom) is all about manipulation and selfishness. I think, if Mom can say "no way this is continuing" and Dad can start showing some respect and dignity toward her, he won't permit Uncle to bash the child's mother. But right now, I don't see a whole lot of regard for Mom so I doubt very much that I'd worry about the racist remark. I'd be much more concerned about a little girl growing up to not respect her mother in every other way!