Its really an tough situation. Explain him about the danger and bad effects of smoking if he not stop it now. I too smoke a lot but it affected my health a lot.I have tried lot of ways to stop smoking but nothing worked well. While I am searching for a good solution I found a good Hypnotherapist from http://www.thoughtsbecomereality.co.uk.
He suggested and provided good solution to stop smoking.I bought stop smoking products and attended various sessions. Now I am able avoid smoking completely and I got good improvement in my confidence and control.