Husband has never had to diet before

My husband was recently told by his doctor that his cholesterol is high, started on a statin medication, and told that the doc would like him to have lost 15 pounds before his next visit (3 months later). I know, I know, 15 pounds - big deal, right? But most of his life he has been on slender side and only in the past few years, now that he's in his 50s, has he developed a roll around the middle. My problem is that he has never had to watch his weight and has no clue what to do. I can sympathize with him. I know it probably seems scary to change your way of eating. But I can't seem to make him understand that he CAN eat many of the same things as always, just in moderation. When I prepare a baked potato, noodles, rice, etc., with a meal, he seems to think I'm trying to sabatoge his weight-loss efforts. He has also  been weighing in on the bathroom scales at least once daily, and I've tried to explain that I've always been told you should weigh maybe once a week at the same time of day in order to get a more accurate idea of how much weight you have lost.  It kind of suprises me how little he knows about dieting since, being female, I've been obsessing over it whether I needed to or not ,since my early teens.  I think we are in need of some written guidelines because he seems to think I don't know what I'm talking about.  Maybe this should be in the section on cholesterol instead of diet?