I've had kittens and cats recover from states that I thought were impossible and some fade over what seemed like nothing.... It is so hard to tell. In the end I think we humans do our best and let Nature/God/Goddess/Bast decide. You, momma-kitty and the little one have certainly tried hard. I hope it ends with a healthy kitten, but whatever happens, remember you did your best and gave loving care.

Good wishes for you all!