Don't put him on antiobiotics. The only thing that they do is kill bacteria, good and bad, and cause worse problems down the line.
There are many natural therapies that are just as effective as antiobiots, if not more. I suggest you try researching this. Here's a good site if you haven't already been http://www.earthclinic.com
If he doesn't have a fever but has an infection it may not be a good sign. The body creates a fever to clean out the toxins and viruses and if he doesn't have one they will just sit there, further weakening the body. I would suggest you try creating a temporary fever for him by putting him in a very warm bath for as long as he can take it. This will help to clean out any toxins and infections he has.