What a terrible time it is for your family. When I was a child my family had "Mikey" a golden/collie cross. He was a protector, a friend, a family member. When I was little, I called him "Mugadoo."
He was so important to me that on my first day of kindergarten my mom got a call from my teacher asking why I kept calling out "where's mugadoo??!" I guess I assumed that I'd be able to take him to school with me. He'd gone everywher else.
My firend with 3 little kids has a golden named Copper who is a mugadoo-clone.
I'm sure that you will do right by Shadow as he has done right by you for all these years. Having been there, my heart breaks for you and your family.