He tries but he cant eat?

It sounds like your boyfriend maybe suffering from an eating disorder, and paranoia/anxiety concerning food. If he goes days without eating in fear of throwing up, this is a serious condition. I suggest contacting a hotline (Eating disorders and prevention) for further information. They may refer you somewhere in your area that has a sliding scale or is free of charge to help your boyfriend out. Smoking does not necessarily evoke such drastic habits. Please call. 1-800-931-2237, or 1-800-931-2237