My dad's smokes about 40 cigarettes a day and I used to, before I realised I didn't need to do drugs and smoke and be edgy to fit in. Even though I'm concerned about my dad's health, I can't do anything about it. You can't force a smoker to quit, you can't force a self harmer to stop cutting themselves, you can't force a drug addict to go cold turkey because there's serious consequences to that. It's an addiction just like anything else.
Reading some your replies (not all), I'm even more disgusted with you people. Have some respect.
I don't know your situation and in my situation my parents asked my sister and I do to this:
My parents were also heavy smokers. Since they didn't have the willpower to quit themselves, they asked that every time my sister or I were with them, and they started to pull out a cigarette, that we would remind them to cut it out, even if it seemed excessive (to me anyway. I think my sister enjoyed nagging them and telling them things like "I want you to be alive to see your grandchildren", etc.).