Boyfriend who smokes cigarettes

So I have a really serious questions to everyone who has dealt or is dealing with a significant other who smokes. My boyfriend has been smoking for 15 years. We're having a baby in January. He has slowly tried to wean himself but I don't know if he can stop completely anytime soon. I'm just afraid that I'll be a single parent sooner than I want to be because of the health risks of a smoker. What are your tips on how to help him quit? Or if you're a smoker yourself, what are some ways that helped you quit ?