Conflicted

I’m in a dilemma! So my Father in laws mom smokes in her home, has done it for years that pretty much when you walk in the aroma of the house is like sitting in a cigarette chamber. She’s never smoked in front of us though.. And so My baby is 2 1/2 months old & we’ve been putting off visiting til he got his first set of shots. Our problem is, she’s been wanting us to visit but I don’t want him to be exposed to that stuff BUT they’ve done sooooo much for us when we moved states so we feel like we owe to them. Call me stupid but how bad will it be for my baby & 3rd hand smoke?!