When my son met my dad for the fist time my dad had flown over to Germany to see us and had been without a cigarette for about 12 hours by the time they reached us and didn't have one the entire time he visited.
I mentioned to him that if he did and was going to hold the baby he would need to thoroughly wash because nicotine on his skin can transfer to the baby. He was respectful on our turf and my son and he had a great bonding experience.
Fast forward 6 months when we flew over to see them. The only two people my son would absolutely not let near him... My smoking father and my husbands smoking stepmom.... I don't think it's a coincidence and I feel like the stench blocked important memory receptors for my son. After a few days of my son screaming when my dad would hold him I asked if he could refrain from smoking when he knew he would be seeing us and again washing thoroughly before holding my son. By the time we left Ds had warmed up to him again but it was sad to see my daddy rejected the first part of our trip.
All I know is... I feel your pain and you have every right to want to protect your child from these toxins... however, we cannot put our babies in a bubble no matter how hard we try.
Best case sinario... Maybe buy some "our house only" clothes and request that said family member not smoke while they stay with you??
IDK, best of luck!