agree with nachu. one of my friend was also a chain smoker. he used to smoke a lot more than u infact.

one day he just decided to quit. he felt uneasy for the first week. next week he had very strong urges to smoke. he wasnt even able to go for his bowles (s**t), but he didnt budge.

week 3 onwards everything normal. no problem at all. even if you offer him a smoke today, he wouldnt smoke