Has something changed with the dog? Have you had him checked by a vet to see if there are any health problems? If no to the first two questions it may be time for training for you and the dog. Do you have a professional trainer in your area? If not, I would suggestion you taking the time to learn how to train this dog properly. Sounds like he could be a good dog if he is trained properly. You should take action before someone gets bite and that can lead to more problems. Good luck.