Dear Tom,
I‘m sorry to hear that you are upset about your relationship with Andy. I think what you have done is right,but if you pay attention to the way of your suggestion, maybe he can be easily accept it.
You'd better tell him more about the danger of smoking.You can tell him that every year hundreds of thousands of people around the world die from diseases caused by smoking.One in two lifetime smokers will die from their habit. Half of these deaths will occur in middle age.Smoking causes around one in five deaths from heart disease.In younger people, three out of four deaths from heart disease are due to smoking. At last you should tell him to quip smoking for the sake of his health.
I think telling him more about the facts is more effective than anything else. I hope you can get along well with your friend.
Yours
lihua