I'm sorry, I don't have experience of having a dog with more advanced kidney problems, so hope someone else here will be able to give you more advice. But I didn't want your question to go unanswered.
The situation does sound advanced. But there are still palliative treatments which may help her live longer and be more comfortable.
How is she now? Is she eating normally?
I don't know how long she has. But with careful management and symptom relief when it is needed, she may have some extra time.
What has the vet suggested?
Kind thoughts to her, and to you all, as it isn't easy when a dog is diagnosed with kidney failure. However long she has, she is surrounded by love and care. It is obvious you and your family love her very much.