Debz,
An 8 cm aortic aneurism is huge and very serious. He should have immediate surgery. Probably a second opinion is needed at this point.
IF he cannot have surgery he will increase the length of his survival time by keeping his blood pressure as low as drugs can get it. The analogy is a hose with a big bulge in it; ONE surge of pressure and that's it. Beta-blockers or calcium channel blockers seem to be the best drugs.
I think the situation is dire and therefore maybe even a surgery with a 75% chance of dying is worth taking. Neeedless to say, you wasnt the best vascular surgeon you can find.
If, on the other hand, his lung condition is a terminal one, perhaps just keeping him comfortable with a low BP is the better way to go.
Ultimately it's his decision and the best you can do is to get him a GOOD list of his options...another opinion is the first step.
IF what he has was called a DISSECTING AORTA (since you said it was bleeding), there's amost nothing that can be done and the prognosis is a quick one.
Sorry for the Hell you are all going through.