I've been reading C.S. Lewis' letters and came across this letter to a friend:
"...I know all the different ways in which it gets one: wild hopes, bitter nostalgia for lost happiness, mere physical terror turning one sick, agonised pity and self-pity. In fact, Gethsemane...what helped Joy and me through it was 1. That she was always told the whole truth about her own state. There was no miserable pretence. That means that both can face it side-by-side, instead of becoming something like adversaries in a battle-of-wits. 2. Take it day by day and hour by hour (as we took the front line). It is quite astonishing how many happy- even gay - moments we had together when there was no hope. 3. Don't think of it as something sent by God. Death and disease are the work of the Devil. It is permitted by God: i.e. our General has put you in a fort exposed to enemy fire. 4. Remember other sufferers. It's fatal to start thinking 'Why should this happen to us when everyone else is so happy.' You are (I was and may be again) one of a huge company. Of course we shall pray for you all we know how. God bless you both,
Yours, C.S. Lewis"
I also helpful to read C.S. Lewis' comments about the differences between the acts of God and acts of Satan. He noted that all acts of creation and creativity are ultimately from God. When Satan acts, he can only corrupt or destroy.