We have a 13 year old DN who has been with us since last September. He was previously brought up by DP's mother who is a bit vague when it comes to boundaries or any time of discipline. I do think she personally feels that authority doesn't apply to her (she had a pretty charmed life until she was unlucky enough to marry DP's dad).
We've made a lot of improvement with him and he's now doing quite well at school, but nearly every week and often more than once we get a call from the school telling us he has been rude.
He's not directly rude, there's no swearing, just very disrespectful, putting his head down, refusing to answer, etc. although he's far from shy and is quite disruptive in class (talking).
He seems to feel the rules don't apply to him. We remove his computer and talk to him about it but frankly it's not much use - he has no respect for authority. When I talk to him I can hear myself going blah blah think of your future, blah blah imagine what it would be like to be your teacher blah blah.
We've had meetings with the school, with him, but he just says what he thinks we want to hear and carries on. He has a very effective strategy of deny deny deny.
Has anybody invented a device for getting through to teenagers?