paralyzed diaphragm- RLD

My father was recently diagnosed with a paralyzed diaphragm and RLD.  He had a robotic heart bypass almost a year ago and never got back the full function of his lungs.  For almost eight months his doctors, including the surgeon, general care, and cardiologist blamed it on fluid in the young.  However, recently they did a 'sniff' test and an utlrasound that showed the diaphragm of his left lung is paralyzed.

I have a handful of questions, and i would appreciate any input on the situation that can be offered.  FYI he is 57 and only needed one artery repaired and his heart problems were genetic, outside of which he did not have any of the commonly associated risk factors.

One, recently we started seeing a pulmnologist who said this is a known complication, but not a common one.  As such, she was saying that it may be hard to find someone to tack the lung down throacitcally.  Has anyone else suffered a paralyzed diaphragm from heart surgery?  And if its not common, then why would it occur unless via fault of the surgeon.

Two, when he was first admitted into the hospital it was at a small county hospital who performed a cath.  Note, he did not have a heart attack, he was admitted after a test showed he was 87% blocked.  after the cath he started thowing BPs and dropped his stats rapidly for about ten minutes.  Neither me or mom are sure what they put in his IV, but the nurse said sometimes this happens from the phenic (sp?) nerve but they dont know why.  The phenic nerve is what is damaged to cause the paralyzxed diaphragm, is it possible this happened during the cath and not the bypass?  Does anyone have any experience with this?

Third, he has a lot more trouble breathing the warmer it gets.  As of 85 weather he cant leave AC for more then five minutes without starting to get confused and disorientated. is this common?

Fourth, the most pressing question i think is on my familys mind is his life expectancy and quality of life.  As there is no cure for the condition, what can we expect.  does anyone know?  The doctors all dance around the question.

Thanks