I sincerely hope your son is OK after the attack and he is not scared of dogs.  Terrible news.

I am surprised that as a pup this has happened.  I understand they play fight amongst themselves (my 10week old pup does with the other two dogs all day) and when playing with toys with me or the wife sometimes he has accidentally nipped, but not bitten.  We've trained him out of this habit already.  Unfortunately if they are showing aggression at this early age its in their breed and not simply misbehaving.  I don't think having two would make any difference as far as the attack on your son.