I watched my brother die of cancer at 22 when I was twelve, as well as my uncle of brain cancer and a few other members of my family. I then had a similar type of rare sarcoma cancer that my brother did when i was 20, and I was just talking to friends about this last night!
I think the most powerful thing we can do as humans is understand our mortality. Once we understand that we're just meat sacks with no universal truth beside death, we can exist in a manner that aligns with meaningful connection.
I advise you tell people things you need to tell them, whether you love them or you think something they're doing is not serving them.
Be justified and trusting in all your decisions for yourself because you have to now.
I'm so sorry this is coming as a shock to you so suddenly. this is hard shit to reckon with at first. But just like my brother said while being interviewed on CNN during our MLB ballpark tour raising awareness in '06:
"I live every day like I'm dying"