when to say nothing at all!?

SO I received a phone call today from my sister-in-law. She just found out that her dad who has been fighting cancer for the last few years, has decided to stop or not continue treatment. As she talked, I could hear the pain in her voice...not knowing how to think or feel about it was how she felt. She wants to honor her dad, but I know....I know she doesn't want to loose him. I talked w/ her for a good while, but knew in my heart there was NOTHING I could say that would make it better...nothing. It is SO hard sometimes, when we want to be able to help other people through their struggles, their hard times, but how? I mean really....I have been there...NOTHING anyone said made it better. No one, not even the doctors could help me for real...they couldn't stop what was happening. In fact, they promised me if I moved my wedding, then my dad WOULD BE THERE...but he wasn't! As I talked to her, I felt the need to say something to make it easier...but I realized that I couldn't, and it is at that point that I think we tend to say things that don't help...we say..."God know's best, or God knows what he is doing" or something along those lines....but honestly....THAT DOESN'T HELP! I know that right now...all she can think is....yeah right, if He knew what was best, he wouldn't be taking my daddy from me....what about my kids, what about me....I need him....his love, his support...HIM HERE! I know that telling her that it's part of God's plan for her life doesn't fit right now, it will be while before that information can be understood...I still have a hard time believing that sometimes and it's been 5 years for me, in fact...even as I type those words about "needing her daddy" I sit here in tears....it never goes away...she will deal w/ this the rest of her life! SO instead I found myself "trying" to be real w/ her and telling her that she needs to go and be w/ her dad as much as she can and to cry w/ her dad and to tell him she is angry that he will be leaving her....to talk, to cry to yell if she needs to! To say to God..."I"m mad,...I don't understand" He is a big God and He can take us mad....He already knows it anyway! Then I came to the point when I couldn't say anything at all....b/c nothing....nothing will change it...
Kelly, I love you, and I am praying for you as you walk through this valley, I know your pain, and hate it for you...I will be here w/ listening ears when you need me...I am crying too! One verse I clinged to is Proverbs 3:5-6 Trust in the Lord w/ all your heart, lean not on your own understanding (b/c you will NEVER understand) but in all your ways acknowledge him and He WILL direct your path (even when YOU can even find the path) I love you.