Aneurysm Coma What Is A Brain Aneurysm?

What is a brain aneurysm? - aneurysm coma

My friends sister had a brain aneurysm (sp?) During the trip. It is in a coma, his brain is not active, but his heart beats. Unplug the machine on the lives of tomorrow. Why is this happening? because he went? Do you have anything cause problems?

Can you explain what it is ... is a 13-year-old will understand.

Thanks