How old is he? Puppies do sleep alot but really hard to say without knowing how old he is. My Zoe did not bark either when I first got her. Count your blessing, he'll probably discover he can bark soon enough.
As for milk, yes that's a no no. Good luck with your baby. By the way, it is a good idea to have nutrical on hand for small babies. I never had to use it for mine and I'd guess that most people don't have to worry about it but it's best to be prepared just in case.