He is a very very lucky man. Many times
People do not show symptoms and the aneurysm blows. Then you are a goner, blood squirts out of any opening it can. I have known two people who have died from this and was working at the hospital and had a code for this. Big big bloody mess. Also while in training observed a abdominal aneurysm repair.
Since the surgery was performed he should have a nice recovery. Now that's luck