Our DS is 7 and is so rude and beligerant it breaks my heart, he has gone to bed having wound both me and DH up to the point of I don't know what to do with him, smacking him doesn't work but nothing else does either he just carrys on being rude and answering back, if we walk away and ignore him he follows us being more and more rude, I really am at the end of my tether have said to DH that maybe we should put a lock on his door because although he can't open the baby gate at the top of the stairs if we shut it then he wakes DD1 up. (this often gets worse at bedtime and he won't stay in his bed or room) I'm frighten'd to just incase the report me to SS for locking him in his room, am thinking that we need some outside help with him. He can be really well behaved while we out but is rude to me if we see anyone we know.
On the plus side he is so kind and caring to his sisters and is DD2's fav person she screams in the morning if I go in to get her as she wants him.