I gave him this site long ago when he told me about the dog being aggressive with his other dog. I have mentioned many times that he needs to separate the dogs at all times if possible and only have them together if they behave while under strict supervision.
On another note, if your dogs get into a scuffle at all its the owners fault. You said you wouldnt report it. What would you in the case of one of your dogs being badly injured? Avoid vet care cause the vet would report the incident? Thats not being real responsible either.
Bottom line is being a responsible owner means keeping your dog completely out of these instances!!