Ah shit. Man I am so sorry as an older brother to two wonderful siblings. I am so sorry.
More than that though, I have a wife and 2 young boys. She's been getting the cancer a bit and genetic testingery revealed she had something awry about her DNA. Much discussion with sombre (and some quite happy to have discovered a rare cancer in our backwater) professors lead to testing our boys and thank the Lord Fuck, they were fine.
Her we still shit our pants over her tests every 6 months. Just us - the boys don't know and never will until they have to*. We all have our problems in life and deal with them the way we can - I would advise anyone who reads things like this to think about if they are ever envious of another's life because I know from experience you never, ever want someone else's problems.
I hope I haven't been too selfish in this post railing about my own feelings just this made me want to share that and I hope it's OK.
I wish you well.
*You may have an opinion on what I choose to tell my kids and I'd ask you to keep that to yourself. Trust me, I've thought my choices through. Thanks