12 year old who is treating his family with contempt which seems to be coming from nerves over exams. School say that he is well behav boy with no school issues

[Runne]

As above

Yep, kick in the hole required.

Seriously? you need to explain rather more to get useful advice.

What exams is he taking? Independent secondary entry?

Why is your 12yr old taking exams? Id rethink that if I were you.

Oh, for the love....

12 year olds often think they know it all, don't give it any air. Just say 'you're being rude, please stop' and then move on quickly. They'll get the message eventually.