First off, I wish you and your little girl the best of luck.
My grandparents mini schnauzer went through this, he was older, though, and they decided after treatment didn't work, to let him die in his own time.
He suffered horribly, and near the end they wished they had put him dowm weeks ago.
So if the vets cannot help her, and it's obvious she won't make it, let her go peacefully.
I am very upset to hear this, my pittie is about 2, and I cannot imagine her being so sick.. I feel very bad for you guys.
Our GSD is having kidney problems, and it is very upsetting to watch her go through this. But at least she is an older lady.
I'll say a prayer for you.. Good luck