Primal, my heart goes out to you and your family.
Children have great wisdom and courage when dealing with terminal illness. Utilize any counselling services offered for you and your family.
I know that you are an educated person who takes control of situations by knowledge (I've seen it before in things you've approached here). Please look for any articles/books on "Explaining Serious Illness to Children" to help explain what is going on to Faber. I am sure at the Children's hospital Juliett is at they will have many resources. At times when you are out of control of the situation, understanding of what you can help with, or help others with during that situation helps you (and your loved ones) through the grieving process.
My heart and prayers goes out to your niece Juliett, you and your family. Faber will be able to look back at his time with Juliett and remember all the fun and love they shared as children.
Congratulations on the birth of your second son Xander. The Lord works in mysterious ways and we must have faith in what he has planed for us all.
If you need someone to talk with, pm me/xfire me.
Your fellow clan "family" member
-Shadow