Hello everyone. Thanks for all the posts.
He has come back to the house again and seems to be a little calmer. I have explained he has a curfew tonight of 9pm and if he misses it he will have to wait even longer to get his things back. Whilst he was in a good mood, I explained again that his behaviour was completely unacceptable and that we can take one day at a time. I am hoping that he will see that if he has a good day where he doesn't swear at us, threaten us, damage our property, adhere to curfews, then we in turn can reward him by giving him a little of what he wants. It has to be done day by day.
Maryz - yes you are quite right, it is impossible to ground him he is too big and we would have to become physical with him (which we have never done) in order to stop him going out. I did wonder about the cannabis side of things. I have been searching his room regularly over the last few weeks and have only found cigarettes.
3littlefrogs - Do you know what signs to look out for re cannabis?
Morningsun - he is one of the oldest in the year. Some of his friends seem to have parents that allow them to do pretty much what they like but I am trying to fight it every step of the way. Last night for instance, out of all the parents, I believe I was the only one that actually knew he wasn't where he was meant to be. I have a system in place whereby I always speak to the parent of the house he is staying at and so far that has worked. Last night was the first time he has defied this. The friend whose house he was at last night had obviously been left overnight on her own by her parents and I despair. It's difficult for me to get my concerns across to him when his friends are all doing the very things I am telling him not to do.
Riven - I'm sorry to hear about your daughter...it's heartbreaking. CAMHS have told me that I should remain hopeful as the fact that he is willing to attend the sessions is a good sign and many children (as you say) refuse to go.
We have always had a happy house where his friends are welcome as that was the kind of house I grew up in with my parents. I am trying to keep the lines of communication open. I know my lovely boy is in their somewhere. When he came home for his dinner today he did say 'thanks for a lovely dinner mum' which I was quite taken aback with. It's so nice when he does say something nice and normal.
I am ever the optimist and hope that one day he (and us) will come out of this the other side. That is why I am reluctant to involve the SS (apart from CAMHS) as at least when he is here I can monitor him. If he does leave home for whatever reason in the next few years, I fear that he will then be in a system where there is much worse waiting for him around the corner.
Thanks for all your posts and sorry that I've not replied directly to you all. I am grateful for your advice.