I had 2 stents just over 2 years ago. With hindsight I know the signs were there that an attack was possible/coming, but you don't tend to think of yourself being that ill until it happens.
I'm currently doing ok, he'll have to start recovering strength and fitness the way I did, small amounts of exercise once a doctor says ok, then steadily increase the amount a little bit at a time. Take an occasional day or two off if there's any problems, and restart at a lower level again.
Some of us suffer from high platelet count, which can cause clogged arteries, so red meat (which contains something that promotes platelet creation) is a treat, rather than a regular item on the table. I'm mostly vegetarian now, and it's not too bad as the choice is much greater these days than it used to be.
Wave hello to the Bear, reassure him, modern medicine actually does work quite well.