Hi. My advice would be to try either contacting a vet, a rat rescue nearby or a rat breeder for advice,although I know that with time zones and everything it may not be daytime where you are. It sounds like this little guy is very young (on a bottle) and I know they can go downhill really quickly when they are babies. Is he still alive? Any updates?
EDIT Hi again. I have just read your other post about this little guy passing. I'm so sorry for you both. Best wishes from Ratbusters