He is 17, smoking since he was around 13, he got into a bad crowd. I have tried scaring him, threatening him, bribing and encouraging him. He wont stop. I got him nicotine gum, he tried one, and then never used it again. I tried to have him fill a chart so i can keep track, he did it a bit, then said he doesnt want to anymore. I feel like saying f*ck it, do whatever you want. Any advice?