To tell a friend or to keep mum

How do you tell a friend to lay off on too much drinking and smoking without being too meddlesome?

I have this friend of mine who has been living such a sedentary lifestyle of inactivity, heavy smoking and drinking. I mean, he's got a nice job and all but what I'm concerned about is his health. I have told from my previous posts how smoking and drinking has caused me to spend a few days at the hospital due to supraventricular tachycardia (SVT).

This friend of mine has experienced the same experience I had with this disorder. However, he never managed to turn things around and start on a better habit. Instead, he continued on with his lifestyle of more than occasional drinking and heavy smoking. I want to tell him to lay off on the habit but I'm afraid that I may seem like being too intrusive of his life. As a friend, I feel like its my duty to share with him a few pointers on how to stay away from experiencing the disease again because the doctor said that it may come back anytime.

Given his lifestyle, it's very likely that it will strike him again. But then again, I might stay mum on this one for the meantime and wait for the right timing perhaps.