Are you able to sit him down and let him know you are uncomfortable with this? I agree with you that it is unsettling. I'd be pretty upset if a family member has this sort of attitude. I have a son in law who does and I loathe to spend time with him as a result. My boyfriend has friends with a similar attitude which makes me cringe too.

My mother was this way during her whole life. I could not mention a person without her commenting on what ethnicity and religion they must be based on the last name which she always demanded to know. I ignored this. She was my mother after all. Now that she is gone I have a lot of regrets about not speaking up about things that bothered me that I never got closure on. This is one of them.

Okay as for your question on how to talk about it. I think that diving right in to discuss it as soon as he does it would be a good call. Ask him if, in this day and age, he thinks it is appropriate. And ask him too if his description of the person(s) matters to the story. Tell him you only want to hear about the story and that the side descriptions have nothing to do with it and you need not hear.