Please help, what are treatments for Coronary Artery Disease ?

Three years ago my father survived two heart attacks.. Now my father is feeling heart attack symptoms, and he's been in the hospital since yesterday. The Doctor mentioned he is a blockage of blood in the Artery.. They haven't done surgery or anything. One Doctor said if the Artery get damaged his most likely not going to make it.. I've been really stressed and worried, is there any treatments ?