I need some advice on a neighbourhood dispute?

I believe that you have every right to call law enforcement. That man AND his dog is endangering both your pets and you. You should not have to tolerate that. You supervise your pets and as long as they are on your property that man has no reason to complain or try to "defend" himself. Even if your dogs do bark at his dog that is no reason for the physical abuse he has committed. Take immediate action but try to get evidence first.