Whether provoked or not, the consequences of having a dog that size attack any family member are too risky to keep the dog around. I wonder if this kind of behavior isn't more common when the dog has been a family member longer than the child. If you and the wife are having difficulty deciding what to do with the dog, maybe one of these dog training centers could help you reach a decision.

Canine Behavior Center 1-888-226-4638

Academy of Canine Behavior 1-800-335-9267

Family Dog Training Center 1-888-226-9054

I hope your child recovers quickly. Good luck!