People who don't give a fudge...

So my kids are dealing with bronchiolitis and are on nebulizers treatments. We are living with my fiancé's grandma till we move into our apartment in a few weeks. So the living room is where they play. Her daughter who is coming down for a few days is a chain smoker and is smoking in the house...where my kids are playing. Should I say something to her or let her mom do something about it? My kids can't better when she is doing this in the house. She doesn't care about them like she says she does. I have respect for people who do it outside and wash their hands before they get near my kids. But this is bull shit. I can't stand the smell and she knows my kids are living here. I haven't said anything bc this isn't my house but I'm fed up with her doing this. I even had to leave the house with my kids bc of the smoke smell in the house.