What is the best way to prevent another heart attack?

I don’t have any advice to offer, but I do offer my sympathies and best wishes. Hope it all turns out well.

Aspirin and plavix (likely for life) along with blood pressure medications (such as beta-blockers and ACE inhibitors), anti-cholesterol drugs (statins), improved diet, exercise, no smoking, control diabetes (if there). Statins are helpful, even if his cholesterol is “good”, because they have potent anti-inflammatory properties.

You should stay healthy and practice the same good habits he needs. No smoking, better diet, outside exercise, take meds, if you have any, as prescribed. By “being good” you help encourage him to stick with the program. He’s a lucky man.