This is a difficult situation. As a player is it worth saying something discretely to the coach? Coach's words/actions were definitely not appropriate, but having had to deal with this sort of thing for a lifetime, I know it's sometimes easier to just pretend like it never happened. With it being the coach it sort of teaches the other players that this is acceptable behavior. So there were several other players that found it amusing, but there was one kid who did acknowledge what had happened wasn't appropriate. It's not something that my son would want anyone to lose their job over or to receive a lifetime label of being a racist. People make mistakes and some people don't know better. I think at this point we just tell him to make note of the incidence and leave it be. No need to potentially risk retaliatory behavior from the coach. Educate your kids to be like the one kid who was able to recognize that mocking someone's race is never appropriate.