Did he see a pulmonologist for a consult on this? If the pulmonologist and the oncologist agree that he is safe to move forward with the final Bleo, with no other risk factors, it seems like it would be okay.
My husband was in the borderline range for doing the bleo or not, and his oncologist felt he could tolerate it. His post-chemo pulmonary function test showed that his upper airways were not damaged by the Bleo. His lower airways, however, are at the 66% function range right now, and he is continuing to see a pulmonologist every few months. The pulmonologist could NOT conclusively say that the damage was from the Bleo, though, as they didn't test his lower airways in the first test.
However, that said, he plays tennis twice a week and plays the trombone in four different bands six nights a week. He just has an inhaler now. So, he's fine, really. :-) Sure, he's not going to be able to scuba dive or tolerate high altitudes, but, meh, oh well. He can still clean up the court in tennis, so, he's happy!
I hope this helps---let us know about the first couple of questions, and that might shed some more light on it in terms of probabilities.