Oh poor boy, I hope he's okay today. From experience I know how horrible it is to watch your pup get thrown around by another dog. My RB terrier X Sandy (10lbs) was attacked while we were on a walk by 2 full grown akita's. The male literally picked him up by his neck/shoulder and shook him around, it was horrible. The owner and I were desprately trying to get him to let go and control the female akita. When he finally did Sandy had some severe puncture wounds and was in shock. After a stay at the vets and a rather long recovery period physically he survived, but he was terrified of large dogs. Before this he was extremely friendly, outgoing and absolutely fearless. After this he wouldn't go near large dogs. It took about 3 years before he was again ok with them, but by the time he passed we had 4 large dogs and he was the boss. I guess based on my experience I'd say get Kaige around dogs you know are friendly preferably a similiar size maybe even similiar breed to the one that attacked him. He may be a bit tentative at first, but if your relaxed and the other dog is obviously friendly he'll probably be fine. I didn't get the chance to do that because of Sandy's injuries, but I'm guessing it would have helped a lot if I had.