1st of all. It's rare that someone "suddenly has an attack". What you are talking about is SDS, Sudden Death Syndrome. 2nd of all, before a heart attack
you get signs. Your dad should get sweaty. . . complain about chest pain
. . . his left arm or shoulder should get numb and most importantly he will get stubborn! Don't take no for an answer if you see these symptoms call 911. You can save his life before he gets it.