I think this little kitten has a lot of guardian angels (well- here at PT they fly in big crews) and now the first thing is he/she has to grow up healthy.
And then you can still see how Momma Kat is with your crew.
I can understand that the vet says that Mommma cannot be spayed before the baby is weaned- but she sure can get pregnant again! Been there (over 30 years ago).