13 year old son self medicating with weed

Hi everyone!

I have a 13 year old son who I believe has PDA. He's recently been self medicating with smoking weed and I really don't know how to deal with him or this situation.

It started in the summer, we tried all the usual methods of punishment such as grounding him, taking his stuff off him, turning off the WiFi etc. He doesn't seem to understand consequences and ran away because we refused to turn the WiFi on. We grounded him and he climbed out of the window in the middle of the night to visit his friends! We tried taking his mobile phone and he became violent, I called the police and he didn't even care. He just sat there and smirked in front of the officer and was disrespectful. He has punched doors, mirrors and throws objects at us if we challenge him on his rudeness or try and take control of a situation regardless of consistency in our approach.

I regularly search his room and confiscate anything to do with weed or smoking. I do not give him any money but he 'earns' his share by rolling for others and he seems to know a lot of other teens who use it so is always able to access it even without any money.

I have tried talking to him to reassure him that we (his parents) are here to support him trying to stop and this is a dangerous path he is taking but he is so cocky, he just tells me that all his mates do it and there is no need to worry! He does it to reduce anxiety and 'chill'.

He was supposed to be assessed in school by an ed psych in September but refuses to go to school a lot so the ed psych made a home visit and chatted to his dad and I instead. We agreed on things like him not having to wear a full school uniform (he wears black skinny jeans and smart black trainers instead), also rather than going to internal exclusion most of the time as this was proving an ineffective method of punishment for him to sit with his head of year instead. He is struggling to go to school at all at the moment even on a reduced timetable and I feel it is only a short matter of time before he is permanently excluded due to his persistent rudeness and inability to do anything he is told to in the class room.

We tried taking him to counselling in the summer, but he refused to engage with the counsellor making our sessions pointless. 

His behaviour is making both his dad and I ill and we are now struggling to cope with him. We have a younger child aged 11 with ASD but his behaviour is not aggressive and we are not having any issues with him.

We cannot go on living like this, unfortunately we do not have any relatives he can stay with to give us a break, I know if I called social services he would never forgive me. Does anyone have any idea how I can move forward?

Any strategies or advice would be welcome as we are desperate, and his abusive behaviour is scaring our younger son which I cannot continue to allow.

Many thanks Marie