I was rereading the book of Job yesterday, preparing for a Bible Study on Wednesday and one thing became very clear to me. If your friend is going through some unspeakable tradgedy it is so much better to simply go and be with her- sit next to her in her grief. Simply do NOT open your mouth to try to explain. Don't try to explain the situation, or God or anything- you simply don't know enough. If you have to say something- say, "I love you," and leave it at that.
The best care Job's friends gave him was when they first arrived on the scene:
Job 2: 11-13- "11 When Job's three friends, Eliphaz the Temanite, Bildad the Shuhite and Zophar the Naamathite, heard about all the troubles that had come upon him, they set out from their homes and met together by agreement to go and sympathize with him and comfort him. 12 When they saw him from a distance, they could hardly recognize him; they began to weep aloud, and they tore their robes and sprinkled dust on their heads. 13 Then they sat on the ground with him for seven days and seven nights. No one said a word to him, because they saw how great his suffering was."
If it had ended there, it would have been ok. But after this, the friends speak to Job. They try to tell him what he has done wrong, they try to explain God and justice and none of it is helpful. NONE of it. In the end, they are humiliated.
Lesson learned: Sit with someone who needs you. Speak as little as possible.