How can I get my father to stop smoking now that he's had a heart attack?

It's very unlikely that your father doesn't know he shouldn't be smoking, and it rarely helps to nag. Ideally, someone other than a family member, such as his physician or maybe even a close friend, should take the lead. Family dynamics may make it difficult for you to get through to him, but someone more detached might deliver the message clearly.

There are certainly programs and nicotine substitutes that help, but as they say, "You can lead a horse to water, but you can't make him drink." When the time comes, remember that quitting smoking isn't easy. Your father will need as much support as you can give if and when he decides to go through with it.

Free will is a really strong thing. If you've exhausted all avenues of having your dad's physicians address the seriousness of the issue with him, there's nothing else you can do. Make sure your dad knows you're concerned about his health because you love him and want him to be around as long as possible. Tell him that smoking is something in his control. Provide him with support if he decides to take a crack at quitting. Beyond that, your dad is his own man making his own decisions...no matter how counterproductive they seem to you.