I don't know where you are but where I am I'd, and I did, report the dog to police. In my area the OSPCA is only concerned about animal safety, not a hoot for humans. You say this dog has snapped twice at your Dad, that's enough, I'd call Police and say I was concerned for my own safety. And there are small children? Police, for me it's the OPP. Since your Dad is the one who was snapped at he should call.
I suppose it would be only neighbourly to inform Buddy's owners. But I've become a cynic after discussing the dog in my case with the owners THREE times I finally smartened up and called OPP. Incredibly I had to call them twice, the second time armed with names and phone numbers of several other neighbours who had also had trouble, including one with a bite to a four year old child.