Not to panic. I was just thinking that the vet had three reasons for saying a couple of weeks won't hurt:

1. She is sure that it is benign, so it can wait.
2. She thinks it is cancer, but it can wait.
3. She thinks it is cancer, but already too late to do anything, so no difference if you wait.

If Kiri is gaining weight and health slowly back, then that is a good sign. I am not suggesting this to make you paranoid. Just ask her why she thinks waiting is ok, and continue: "is it because (1, 2, 3)?"

HUGS - keep the faith.