[Vickeryyorkie]

I have a baby that turned 2 weeks old today. His mom had a c-section but has been nursing him. My problem is I think he came early, because he does not nurse good, he seems slow, so I have been helping by feeding goat milk with a few drops of karo. He started out at 3.3 oz & he is only 4.0 oz as of today. And as of today I don't think Gracie is helping him poop or pee very well.
So my question,s are how do I get him to gain weight ? & keep it. And I tried to help him poop & he did a little but not much & did not pee at all. I did the warm cotton ball as well. I know Gracie has milk because I have a 3 week old orphan girl & she is nursing on Gracie. & she is doing great !!!
Thank you for any help you can give me.