Not really my field, but there are more or less recognised criteria for operating AAAs. Generally, smaller aneurysms, asymptomatic and non-progressive aneurysms are best left alone. I don't know where your relative fell in the risk profile.
There's a reasonable summary here:
http://www.jr2.ox.ac.uk/bandolier/band27/b27-3.html
Just as in aviation, most of the time there's no absolutely right answer (except in retrospect!). SOPs will see you right most of the time, but occasionally one gets a gut-feel about things that I have learned to listen to.
And the most surprising people do survive catastrophes....
