Post bypass surgery complications - Right lung fluid retention

Hello,
My Dad is 70 years old and he had bypass surgery earlier this year. While in the hospital recovering they said had had fluid on the lung. But released him to come home. A couple of weeks later at a follow up visit to the doctor they took a chest x-ray and he still had the fluid on the lung. They send him to have the fluid removed. He came home and a week later he had another x-ray and the fluid was back. So the heart doctor sent him to a lung specialist. The lung specialist ran all kinds of tests even drained the lung again to test the fluid. He sent my Dad back to the heart doctor because he could find a reason for it. In fact he told me Dad that is was not usual to see this after open heart surgery, but on the left side. My Dad's right lung is the one that is filling up with fluid. So we went back the the heart doctor and he said that the surgeons took a vein from that lung and that we would have to see the surgeon again. Can you help me understand what is going on, what this could be, what causes it and what is the course of action to correct medically speaking?
Thank you

[KarlT]

I am 70 and two years ago I had triple bypass and the same wet lung symptoms. I have controlled it to a great degree. It take two steps: First, have him sit with his head tilted back and deep breath where the air accumulated in the lower diaphragm area. Inhale on a slow 6 count, hold a 3 counts and exhale, as one would slowly exhale smoke, Do this for at least 10 cycles three times a day. This will expand the lungs, and at the same time develop stamina for more walking exercise.

Make him walk or do more and more aerobic movement and the Lings will stay dry.

I also sleep with the wet lung up on my side. Tilt head back and get maximum easy sleeping air flow.

As soon as I neglect the program the discomfort returns.