smoking

My son was just recently diagnosed with RAD (reactive airway disease). He is only 3, he has had problems since he was a baby, with sleeping and waking up to catch his breath and wheezing a lot. Most of the time it's during the winter season. Well me and my husband and the kids (3 and 6) just moved into his mothers house (about 6 months ago lol) and she smokes (cigarettes of course). At first I tried to ignore it and take the boys to the other room if it was too bad. Recently his step brother and his girl friend moved in too, they have no where to go and want to try and save up. He smokes also. After our 3 year old was diagnosed, my husband talked to both of them about please smoking outside, because most of the time he is coughing at home and I'm sure it's because of the smoke. Well they did for a day 🙄 and my husbands mom is going through health issues too, she keeps saying she's stressed that's why she's still smoking. She tried quitting at least 4 times since we moved in. I can understand why she's stressed, having all of us there and bills piling up. But it's not good for either of the boys to be around the smoke. I'm so annoyed and miserable, I bring it up to my husband all the time and I feel like I'm just being annoying to him. He knows it's a problem but we can't afford to go anywhere and it is her house, so it's kinda hard for us to tell her what to do. I feel like it's over her head anyway because of her own issues, she doesn't think about the kids. Has anyone dealt with this kind of situation? To add in there, I know a lot of you are going to say, it's not good for the kids from the beginning, if you knew she smokes why did you move. Well it wasn't this bad before and she smokes more and more because of all the stress in the house and having his step brother do it too. That doesn't help, I have said to his step brother, take it outside, this isn't your house and we have to keep as much out as possible for our kids. Well still does what he wants and the smoke esp when the kids are in the other room. Like it's not going to travel 😡 as a mother I am so irritated and just want to cry all the time. I feel so helpless to my kids.