Great discussion on suffering!
Wow, what a great discussion on the SFA site on suffering from my August 1 post, 'Why does God allow suffering?'! Really good insights! In particular, someone asked about how to help his/her sister who suffers much. As we all do, the sister struggles to handle suffering the moment it hits in a Christ-like manner.
Might I suggest meditating on the seven "words" that Christ spoke from the Cross. Please check out my post on the SFA site from April 14, 2006, "The Seven Last Words of Christ".
I would specifically point to the word Christ cries out when he is experiencing some of his greatest pain: "my God, my God, why have you abandoned me?" At this moment, Anon, He is uniting himself to your sister (and to any of us) who feels "so alone in her suffering", as you wrote.
Does this mean that Christ lost his faith in the Father on the Cross? No. One of his next words is "Father, into your hands, I commend my spirit". He is one with the Father always. But, he is showing that, in his human nature, he is truly one with us, even experiencing the greatest pain of all: the pain of feeling alone.
Christ knows exactly how your sister feels, and is probably the only one who really does. And, she knows how He felt. She is united with Him in a very intimate way. If she can unite her words at the moment of agony to his "words", then I would say she is being about as Christ-like as a person can be in her Grace-filled situation.