Anxious argumentative 9 year old

[user1478431192]

I was wondering if anyone could offer any advice. My son is a good kid but has been through a lot. His dad left at my request about 3 years ago as his behaviour around us was destructive...drink, prescription drugs, cannabis. Unfortunately since then he has not seen my son and daughter a handful of times as he has continued his cycle of drink and drugs, prioritising this above his children. My son has friends and does ok at school but he can be very anxious in social situations. He is also quite controlling in that he wants me to drop everything to attend to his needs...if I'm on the toilet he demands to go on it, he won't go upstairs on his own, he can be quite unpleasant to his younger sister and still has tantrums. We were at a party and all having a good time but he made a scene and started crying his eyes out and demanding to leave, he has done this before, even though there were many children to play with. I feel at 9 years old this shouldn't be happening. He disagrees with everything I say...I say it's cold, he has to be hot etc. I just feel like there are things he is not talking about and his dad has left him fling quite angry. He does not have hobbies and won't join clubs...I have taken him to rugby and football but he Cris and we have to leave. His only interest is playing the computer and watching you tubers. I have a lovely and supportive partner but his behaviour impacts on all of us as a unit as I feel stressed and this has a knock on effect. I work and try to do everything I can to support him, make sure he eats well and has friends over, spend time with him at weekends but I feel nothing is good enough as there is this underlying issue...please any advice I can't have this continue as it will only get worse.