The basic premise of all homeopathy is that you start with the contaminant and repeatedly dilute it to the point there is not even a single molecule of the original contaminant left. At that point the water is supposed to have the "memory" of the contaminant and drinking it is supposed to help you fight similar contaminants. The more times you dilute it, the "stronger" the homeopathic effect is supposed to be. Hence the joke, "I forgot to take my homeopathic medicine and so I overdosed."
In this case the seed contaminant was rabid dog saliva, but it was roughly equivalent of the rabid dog drooling in Burrard Inlet and you scooping up some sea water in California and claiming it's related. Not a cure, but the kid wasn't in any danger either. Total placebo effect at best.
Edit to add: often homeopathic medicine can come in pill form because when it's all done they remove the water too. :doh: