Did the police officer give your son a written citation/ticket stating he must get rid of the dog? If not, then your son does not have to get rid of his dogs. There usually are noise ordinances which could explain the complaints about the barking. However, if the dogs are not barking, and your son has proof, then, he may file a complaint for harassment against the neighbor.
Attorney
8+years of experience in all matters of civil litigation and Hearing Officer/Arbitrator