As long as he is reasonably healthy otherwise, with no major medical difficulties or history, he should do fine. The procedure is pretty perfected now.
One thing I will warn you of is that for a few weeks after the surgery, he may be "different"...crankier or more short-tempered than usual. My DFIL had open heart surgery 5 years ago, and for a couple of weeks post-op, this man, who had generally been an easy-going, personable guy, turned into a real bear. It got to the point where my DMIL asked the doctor if it was possible that he had had some complication that caused a stroke or lack of oxygen or something. The doctor told her that often when someone has been on a heart/lung machine(which most cardiac surgeries require)they have a couple of weeks of personality change, until true equilibrium is restored. That was the case with my DFIL, but as time went on, he did settle back to his normal self. When I asked a couple of my friends whose parents had also had open heart surgeries, they said the same thing! Some kind of phenomenon, but one that no one mentions. I mention this to you only because when it happened to us, it was quite worrisome until we had an explanation for it, and saw that, with time, he was indeed returning to "normal".
I wish your father good luck. I will keep him in my prayers.