I think this is a realy hard one for both you and your mum. My father was a smoker and from the time I can remember he had the most horrid cough, our house, our car, our clothes, everything smelt of smoke. Dad started smoking at about 5 years of age. He would light the fisherman's pipes for them. He was addicted to the stuff and try as he might he could never give it up. Please be patient with you mum let her know that you are there to support her as much as you can but still hold your line of no smoking and washing hand around the kids. Unfortunately for me and my DD my father died of lung cancer 10 years ago aged 66 so she never got to meet her wonderful poppy Ted.