Yes, I do. All fo the doctors at Eastern are excellent, so if she says he is fine, then he is. He is awfully small though for his age. You might try buying some PANR from the online stores here and switch him to that. I have heard many people find their chins gain weight very well on that.
Also, remember with the antibiotics, you will need to add some acidophilus into his diet. Antibiotics kill all bacteria, including the good bacteria chins have in their gut to aid in digestion. So you need to replace that bacteria to keep him from getting an upset stomach. You can use the same acidophilus people use, just sprinkle a half capsule over his food. If he won't eat that, try giving him a chewable acidophilus tablet, they are flavored and so more palatable. It's not the preferred method but it's better than nothing.