I'm very sorry to hear of your loss. These particularly bother me as I've survived two aneurysms myself, one a ruptured cerebral aneurysm, the other an abdominal aortic aneurysm. The AAA was discovered incidental to another illness and was repaired before it ruptured. The cerebral aneurysm ruptured when I was 41 and I never had a clue there was anything wrong. It is not at all uncommon to be completely unaware of them. As a doctor once told me, the first symptom of an aneurysm is often sudden death.
With new technology now available many aneurysms, mostly those outside of the brain, are now detected before they have a chance to burst. There are risk factors associated with aneurysms. As someone mentioned, it is thought that there is a heredity component to aneurysms and in my case the doctors recommended that 1st degree relatives should be checked. Recently, it was discovered that my near 80 year old Mother has an aortic aneurysm.
Other risk factors are thought to be high blood pressure, certain diseases and, statically, smokers seems to constitute a higher percentage of aneurysms victims.
Again, I am very sorry to hear of your loss. Our thoughts and prayers are with you and your family.