Need advice

I have a 5 week old baby and I'm dreading Christmas this year because my SOs whole family smokes in the house. We spend Christmas eve with his family. I've told his mom I don't want the baby around smoke but they don't respect that and continue to smoke around the baby.

I don't want to go there for Christmas but if I don't my SO and his family are going to be upset as some of them still haven't met the baby.

I also don't want to bring any of his stuff like car seat into the house because then it'll stink.

What should I do?? I feel like I can't win and either way someone is going to be upset.