I keep reading your this thread over and over... And I guess there's two reasons I haven't responded up until now...
My own stuff (fears, anger and such at my mom's Big C dx) and knowing that nothing I say can make you suffer any less, it may even come across as trite.
So why did I respond?
Idk, not so sure, couldn't keep reading it over and over and still say nothing, that seems callous to me.
I lost my best sibling, 16 years older than me, more like a back up daddy.
It leaves a gaping hole in your life and heart, but with time you learn to live with the loss and I guess endure it.
I pray you find healing in the fact that your sister has found peace from her suffering.