Second/third hand smoke from FIL

My parent-in-laws are nice people and they treat me very well. They are willing to care for my baby when I go back to work too. I see that they’ve raised my husband to be a wonderful person, and they dote on the other grandkids and I don’t mind them taking care of my child. However, my father in law smokes and I find that a dealbreaker. My husband has been telling his father to stop smoking for years but he can’t quit. Even now, while I’m pregnant, he still smokes when I’m at their house and I can smell it on him when he comes back into the house and it makes me uncomfortable. My husband notices this and tells him to change clothes when he comes back in. Having my in-laws care for my child is the most economic thing for us to do, but how do I reconcile with the fact that I don’t want my kid exposed to second/third hand smoke? I don’t think simply telling my FIL to stop smoking will work at this point cos my SIL did do this when my in-laws cared for their baby and it caused some rifts between them.