Coco, some owners indulge their dogs and become ruled by them. The dogs take control and do their damnest. A dog is of course a pack animal, and knows that it's necessary for some one(dog) to be a leader. If the human won't then they will. This doesn't mean they're any happier for it, as the reponsibility of leadership can be stressful. Dogs need discipline and keeping in their place. When this happens they can be the most wonderful friends and companions. If it goes wrong they're Royal pains in the backside. If your doggie next door has become spoilt and troublesome it's unlikely that those who caused this can resolve it by themselves. If they wanted to that it is! Maybe they find his idiosyncrasies endearing? If they wish to change the dog, then a dog psychologist would be worth speaking to.
Clam