HELPLESS

Hey guys..i just found this community and i think its great. I hope u dont mind that i joined, even tho im a nonsmoker. My boyfriend has been smoking for about 5 years (hes 21) and is in the process of quitting. Im really proud of him for doing it but the problem is i just feel so helpless ! I want to be able to help and support but im not sure what to do coz i have no idea what hes going through. Both his parents smoke and arent happy about his decision to quit and he still lives with them, so hes finding it very difficult. I dont want to sound like a nag to him, but at the same time i want him to realise he doesnt have to listen to his parents (i know that sounds harsh). Any tips as to how i can help and support him without being a nag ? Im completely at a loss here. I want him to know hes not alone.