
Me personally I would work more on his obedience. Also get ur children to work on his obedience too. Do not allow him on furniture.bed/ect. When u give him his food make him work for it, like sit/down ect. Teach him an out command (play fetch and when he has something tell him out to realease it). Always praise/treat for a job well done. He sounds as though he is the alpha in the house not u or ur children so he is sorting things out the only way he knows how to. Sign up to a couple of obedinece classes as well as other fun dogsports (flyball,agility) and have ur children do them with him, and u must practice at home as well as in class. The more obedience u have over ur dog the better. U have to teach him that u are the top dog in the house as well as ur children and make him the bottom of the pack. Only pet and play with him when u want to not not when he wants to, and u must end all play not the other way around. Have a special toy that only comes out at play time and gets put away after when U are done playing. Teach him no bite never to old to learn. U can have a set up, keep him on leash and have the children yell or u but have some one strong enough on the other end of the lead so if he goes to bite give him a correction (like a pop on the lead) and say NO in a low growl voice and put him in a down position (the person on the other end of the leash does this), then praise/treat once he is laying down. Do this a couple or more times through the day so he realizes that if someone raises their voice that he is still ok and no one is going to get hurt. Dogs feel vulnerable in the down position thats why I suggested to put him in one, it shows them that they are still safe and nothing is wrong.
Please don't give up on him just be a little more patient and work harder on the obedience and setting things up so he is put in that situation and can be safely and easily corrected. He will not be corrected over night but if u take the time and work with him everyday I'm sure he will be a better behaved dog. Just make sure ur whole family is involved with everything and u give a lot of praise/treat for good behaviour.
Good luck :) This is only my opinion:) Junior my male (boston terrier) has been a real hand full and would try to nip strangers if they came to close to me but now he is doing great and a real joy to take outside and loves to great people. They can be turned around but a lot of time/devotion/patience on ur part if u really want it to happen. Wishing u the best of luck and ur little man :)
ttfn :)