Aw OwnedByCritters sounds like a concerned animal helper
In the name of kittehs and critters of the world I thank you
from the bottom of their cute little hearts.
I truly think your kitten will be all right. He needs some care and some special diet but I've been there. I had to kittens with constant diarrhea and farts and they grew up to be magnificent big cats, close to 10 years now (well now they're with my parents) it took us a while to get rid of it but they got better.
Also I had 2 kitten brothers who gave me a hard time with worms I had to keep trying with the vet, trying different things because they were infested real bad. They also became beautiful loving cats.
I'm sure under your care that kitten will be all right now
Rats are so cute! I hope your rat gets better as well
P.S. Again...Thank you for rescuing a kitten