What is the best way to prevent another heart attack?

My father had a heart attack today and I’m extremely worried. He is such a strong man and while he was driving to work he knew he was having a heart attack n drove to the hospital. He’s doing good with 1–2 stents In his heart. His cholesterol is good so we don’t know why he had it yet. Anyway can anyone tell me about stents. I’m afraid if he has another heart attack he won’t b so lucky. I want to do everything I can to get my dads heart healthier. What do I do?