That's why you NEED to train him.
You may need to buy a muzzle for him ( one that doesn't hurt or anything) at first. It sounds like he is out of control, through no fault of his own, he thinks he is the alpha dog - the boss of the family. You need to correct this, establish yourself as the "top dog." You need to probably keep him with you, on a leash. Train him with simple, basic commands. Does he have a crate or a special place he likes to be? The sonner he is trained, the happier he will be, honest!