Ah but there is a long history of intense scrutiny of everything about Black people: our hair, what we eat, how we interact, etc. and the white viewer is primed to classify what Black people have as worse. Why else would the darkest Black skin (with its typically smooth texture, ability to withstand sunlight and resistance to sagging and showing age) be considered worse than pale skin (with its inability to withstand sun, skin cancer-prone, freckling/sun spotting and myriad irritations and rashes) be spoken of in terms like alabaster and clean and pure?

What your cousin said IMPLIED that the Black smell was worse. Otherwise he wouldn't have felt the need to mention race OR he would have said something like,"I notice the Black players all smelled like smothered pork chops" or something else delicious. The most innocent reasoning for mentioning a different smell was to invite parental direction/input. He wanted Uncle to say something that either gave him permission to start denigrating other differences or explanation that gave him permission to just be cool with the new Blacks like,"Son, women smell different from men. Don't look for reasons for differences but the ways you're alike."

Jokes where 'how different Black people are' told by white mouths are only funny to whites. My last paragraph in my comment above had two-fold intentions: 1) to illustrate that all people think other people smell like objectionable things and it's rude & offensive to say it to those people! and 2) anyone would be sensitive about their mother being joked about while she was in the midst of/barely removed from crisis.