Mbluish, I don't believe there are any quick fixes -- just look at the rest of the world -- but as DoroMona says above, if there was some way to slowly begin to open a dialogue between the four of you, maybe if your parents could really convince your husband that they truly love him and have been acting out of a state of total ignorance, you might be able to get somewhere. I would favor a very cautious approach, with the accent on a whole lot of respect for your husband's wounded being.

Maybe if you got his permission for them to WRITE to him, say, to try to explain themselves.... Gosh. I truly do not know.

I don't have much racial diversity in my family so it hasn't been much of an issue, but I'll bet there are people out there on the forum who could give you more specific advice, based on their own experience.