MIL and FIL usually pick DS (7mo) up from childminders once a week - not for my convenience - just so they can spend time with him. They also have him maybe once at weekends.
My FIL smokes; outside at his house and in his car when MIL isn't in it. MIL doesn't drive.
I got a lift from him a few weeks ago for the first time and the car reeks of smoke, strands of tobacco littering the bit near the handbrake etc. I felt I couldn't say anything. But I've just realised my DS will be out of his baby carrier seat soon (it's our seat they use) and into the larger seat which is permenently fixed into the rear of their car (they have another GS who uses it once a blue moon). I really don't fancy my DS sitting in a chair that's going to be really smokey, even though TBH he's not on long journey's with them.
What do I do? AIBU to tell them to clean the seat and then take it out and only put it in when they pick him up? (this will be impossible - neither of them know how to fix it in!)
I think I'm just narked that my FIL smokes full stop.