I, too, would love to see a video of exactly how he "attacks", visuals are always helpful Also, if you didn't receive the puppy until five months of age, there's no reason to immediately conclude that his HA behavior is a genetic flaw. There are any number of things his breeder or former owner could've done to sponsor such a temperament in a young dog, and then switching homes halfway through his puppy hood could've simply cemented his already insecure grasp of his environment. Unless his breeder has produced other HA dogs, and other people interbreeding his family have produced HA dogs with a regularity, I wouldn't worry too much about him producing maneaters just yet.

ETA: You need to work on socializing him with your family and other people while he IS still a puppy. If he's left with the impression that he can bully your wife and children and get you all to himself, then he'll take that and run with it. If he's under a year old, there's really no reason that your wife shouldn't be able to help handle this situation with you, he's still a baby and still very impressionable, so the quicker you start to build new, POSITIVE habits with him, the better. Right now, he's figuring out how he relates to everyone else around him, so the WORST thing you can do is just let him get away with his behavior, which is what you'll be doing if you simply remove your family from the situation. If he growls at someone, they should ignore him, not become flustered or intimidated by him, and CONTINUE to do whatever it was they were doing to him or around him. If he bites at someone, give him a nice solid smack and a firm NO. Any behavior that is playful, affectionate, or remotely positive towards a family member should be rewarded. He needs to know that people are to be ENJOYED, not something to be afraid of or aggressive towards.