I am so sorry for your loss.
My grandmother, God rest her beautiful soul, valiantly fought breast cancer twice but, when it hit her liver, she knew it was the end game.
My sympathies to you, my dear. I’ve noticed that many don’t take seriously the devastation of a major cancer in people that are “old enough to die.”
I have a rare genetic mutation myself, I inherited it from my mom, and likely her mother, who was never tested. It was a real eye opener to know I have a 90% chance of cancer by age 60. But knowing gives me freedom to plan each day.
All I can say to you is get your testing done. Now! For you and any children.. There are drugs and courses of treatment specifically for inherited cancers. And every day it is becoming clearer that most cancers are inherited. Targeted treatment is the way of the future.