Airborne6771,
Sorry to read of your frustrating situation.
The details that you give are probably not entirely accurate -- aortas can be repaired or replaced but not as part of a coronary bypass operation. However, whenever I hear of a patient being told to enjoy the time they have left, I ask them to seek another opinion. The original doctor may be right, but why trust one opinion. I can tell you that we see numerous patients come through here who have been told to "enjoy the time they have left", only to find that they have several good treatment options.
Seek help from a major institution. Make arragnements for your dad to meet you somewhere, or bring him near your house. Many large centers are available throughout the country that should be able to review your dad's records/films/studies and offer a state-of-the-art opinion.
Good luck.