
I'm very sorry to hear this. And my heart is going out to your mother.
I've not had a dog with this problem, but I'm a nurse and know the sad prognosis in humans.
The biopsy shouldn't be too stressfull though. It is sometimes better to know for sure what you're dealing with.
I understand that you're unwilling to put this old girl through unnecessary pain and stress, and of course I agree with you. But maybe if this could help your mum?
Keeping fingers crossed that the Prednisolone is working.
Karen