Lauru, I hope your mom is getting her treatment from excellent doctors who are familiar with heart health in women.
You mom's condition sounds very serious, but if she's getting proper treatment she can tell you she has years still to live. I've been through a heart attack and met many women who are living with heart disease.
I know it is hard to hear about a life-threatening condition in a parent. So, I hope you are able to help her look at the ways she can have the best quality life in her remaining years - that positive view will help YOU.