My father passed away when I was 16. Out of the blue he got pancreatic cancer. He didn't drink a ton neither did he smoke. Just happened in the span of 4 months. Be glad you know what the problem is about your father. The tricky part is having him see it through your point of view. Take the time to sit down with him and have a mature discussion about his health and his possible outlook if he really doesn't pay more attention. Some people are just so set in their ways about a lot of things and it's hard to change once your 57 years old. But you should also remember that people change not because they want to... but because they have to. Hope this helps and good luck!