Your brother has a dog that "barks his head off", your brother knows this, and your brother failed to fix a problem that is a nuisance to the neighborhood. Sounds like your brother is a real jerk who deserved to get sprayed with the hose.
Tell your brother to smarten the heck up and fix the darn noise problem that HE is responsible for. Some people have to work, and others have to work nights. You ever tried to sleep during the day while the neighbor knowingly allows his dog to bark incessantly, knowing you have to go in for the midnight shift in a few hours? It SUCKS.
Whether he knows it or not, your brother (because of his dog's nuisance barking) is "That Guy" for his neighborhood. He's the guy that everybody secertly hates, because he's responsible for a problem that affects everyone around him, and he's doing nothing about it. Chances are, he's probably in violation of some noise ordnance, and his neighbors have simply been nice enough to let it slide.
He was good to not react. He deserved it, and he knew it.