I agree!! this is a touchy area cause it takes faith and no doubt!! to overcome issues like this.

Like your friend (I'm sorry for your loss) that had cancer!
Its actually two different realities - its just which one do you believe and hold onto.
If you believe you have cancer and keep telling yourself you have cancer and your dieing then ...
But if you hold on to the reality that God has cured you then...

But I can't imagine how hard something like this is and these are the things that test your faith like crazy and most of us don't want to be tested like this..
"If you have the faith the size of a mustard seed (then smallest seed) then you can say to this mountain (your issue, disease, etc..) move and it shall be moved"

But God has his will and we have ours.. and thats what makes this different at times..

Its like that girl that got shot and killed because she said she believed in Jesus or the missionaries that get killed and raped for preaching the word of God.. Its not magic - you can't say Jesus, Jesus, Jesus and you'll never get hurt, killed, or avoid any bad things happening to you but, on the other hand you can say Jesus, Jesus, Jesus and be covered from all these things.. It's hard to explain but bad things do happen to saved people that have 100% faith in God!! Its part of the curse (adam and eve) and even though the blood of Jesus saves us eternally & physically - God's will, our choices, and I'm sure 1,000 other things come in to factor with issues like this..