Bella, I have just read your posts ad I am so so sad for you. I found DS very very challenging, pretty well from birth. (never stopped crying and I had no help apart from H). At 9 we had suffered 5 bereavements in 4 years and 2 people he was very close to. And that is when his rages started.
His Dad and I both struggled but the relationship between him and his Dad was apalling.
I don't stop his pocket money, or really 'punish' his behaviour (unless he is mean to his sister), but we do talk a lot. His self esteem was none existant. I spent a lot of time praising him and reassuring him how much I love him. For some reason, guilt and shame make his behaviour worse, where with a lot of us, it brings us into line.
I use the 'I' message. ('I am unhappy that this has happened because.....' rather than accusatory statements that make him feel he is to blame.) I also ask how 'we' can find a solution to what is bothering us.
'It is difficult for mummy if you don't come in on time because she is on her own with DD, so it is not easy to just pop out and find you...this means I don't have time to do X or Y with you...how do you feel I could help you remember to come in on time?' We got him a mobile phone which is a big help. I give him a 10 minute warning that it is nearly time to come in.. then 5, then, (and he usually comes in) that I want him home now.
It isn't changing overnight but the progress since this time 6 months ago is remarkable. Last night was probably 50% my fault because I do get frustrated and tried to assert my parental authority whch achieves zilch. He responds much better to being treated
older than he is.
The phone is a good one as I will say, ''your phone is being put away until you have done so and so, and no phone...no going out.'' I don't take it indefinately because he just behaves worse because he feels hard done by. But if he realises a change to his behaviour will get it back, it mostly works.
It is so disheartening and I really feel for you. Finding his 'key' will come and things can be turned around, even though I truly understand how you must feel right now.
We have had CAMHS, a social worker, and a mentor, and mostly it is lovely now to see him progressing. There will be a root cause and it may surprise you but don't give up Bella. I am sure you do but look for and give him the opportunity to 'shine' as they get sucked into the spiral of negativity that their own behaviour causes.
Sorry for rambling and not sure if my experiences will offer any help or comfort but I really do empathise.