I am so very sorry for your situation. I have experienced having a beloved Yorkie with a terminal illness. We had LacieBug for almost 5 years never knowing what day would be her last.
My best advice is love Kissi all you can, make her as comfortable as you can and know that you are doing all that is humanly possible for your beloved.
I will keep Kissi, you and your entire family in my thoughts and prayers. If you need to talk, please pm me and we can exchange phone #'s.
Hugs
--cindy