Are you sure it was even a heart "attack"? Just because he is hospitalized doesn't mean it was a heart attack.
My AXH had a heart episode when we were about 37ish. His heart rhythm got all screwy and fast and would not slow down. They had to take him from his work to the hospital in an ambulance, where they ended up sedating him and applying the paddles to reset the heart beat. It was near Christmas and the hospital staff said it wasn't a common thing, but not unheard of and that they call it "holiday heart" as they usually see it during the holidays when people are stressed and over indulging. Alcohol,caffeine and stress being the main causes. He had far too much of all those tings at the time. (Truth is, he still does) For a while he acted all heart healthy cutting animal fats, salt, caffeine, taking his vitamins...all so he wouldn't have to stop drinking , which I am sure you all know was likely the biggest cause of this having happened to him. The night before he had consumed copious amounts of vodka mixed with cola and still smelled of alcohol when I got there to bring him home.
I hope your lawyer can help you use this latest medical crisis your X had to help keep your children safe.
I also hope for your kid's sake that this is an eyeopener for him and he starts treating his body with more respect.
Big Hugs!