Denise, I am so sorry. Don't ever second guess yourself. Whatever decision you make is the right one. I went through this with our first grey, K.C., who had osteo. It was her front left leg and she was 12, and she did wonderfully.
It's a long haul, but you are strong and so is Brooke, and the pain will go away which is the most important thing.
I'll be saying prayers for both you and Brooke. I wish we lived closer. You need all the support you can get and that is why this board is so important in times like this. Will be waiting for hopeful news on Monday evening.
God Bless.