You can lead a horse to water, but you can't make him drink. Unless he is motivated internally to do this for himself, all your good intentions are going to be wasted, I fear. It can't hurt to try, but don't be disappointed if the advice isn't taken to heart or followed. Another quote that I saw recently in my workplace newsletter comes to mind: "A good scare is often more valuable to a man than good advice". I'd hate to see it come to that, but perhaps it will take a serious run-in with a bad bout of hypoglycemia to wake this guy up to what is happening to his body and get him to take action. Good luck!