So sorry to hear it. I'm so sorry your family has to deal with something like this at what ordinarily should be a very happy and peaceful and contented time for families everywhere.
It just doesn't seem fair, does it?
VERY small comfort, but - posting about it here on DU might help a little bit. You have lots of company, and lots of sympathy, and lots of empathy. You have no idea how much is there waiting for you to tap into it! Many people here have shared health crises of their own or a close loved one or friend, and the rest of us have banded together to listen, to support, to console, to commiserate, or just to be there. I have found that DUers have very broad shoulders and very large ears, and many many virtual boxes of kleenex. Someone's always here. Someone's always awake. Someone's always paying attention. You don't have to struggle with this alone.
I can't adequately explain to you what it meant to me after my mom died and I posted a brief post about it. I was almost avalanched with people's posts here, sympathizing, empathizing, offering comfort, offering their own stories of grief and mourning and many a death watch. We knew she was on the way out. It was a long, miserable, lingering illness. We knew she was dying and that the end was coming soon, but it still wasn't any easier to cope with. What DID make it easier to cope with was the love and support and kindness from people here. I was so touched. It was more than seven years ago and I'm STILL touched by it. I still think about it and get choked up and feel so grateful for those kind words and heartfelt sentiments that people expressed.
You don't have to struggle with this alone. You won't be alone in that pain. You'll discover that a lot of people here - are there - standing next to you.