Hi
Sorry you're having such a hard time here, just a thought from my work I have done with teenagers and families . Do you have anyone within your family who can get you all together as a family and help you all to talk things through ?
The other thing that may be worth doing is to come up with a family contract , which sets out what everyone is prepared to do/ not do and the consequences for not doing so. This will put the responsibility for each individuals behaviour back on to them.
Whilst on the subject of behaviour it would be a good idea to have a discussion and or record the behaviour that is not acceptable for everyone and any consequences you want to impose. However you can start on a positive, by identifying three things that you respect about each other.
These are only some suggestions from my experience, please remember that YOu are the person that knows your son and family best, so what I am suggesting may not be suitable for you all at this time.
I would also sugest speaking to your sons head of year or school headteacher , because if you decide that handing responsbility back to your son, some of the consequences could be that work is not completed on time etc, if this is the case the school can then implement their own sanctions, and support you, also if your son sees yourself and the school is communicating on a regular basis, his behaviour may change, of ourselves you may be surprised, it could be that when he is given responsbility for his own actions, work starts to get completed.
If you want someone independent to help, there are professional mediation services for families , just do an Internet search for your local area.
Good Luck,