How common is death by aneurysm?

My best friend's mother just had one tonight and she is in the hospital. I am incredibly worried to death. Do many people make it out alive after having one? All of a sudden she started feeling pain in her head and felt cold, we had to put ice on her head. She was so weak and cold, totally out of it, mumbling random words and screaming helplessly. I need some good information on this, no sugar coated bull ****... Thanks