Dh home now and bloody useless. Shouted at me so ds could hear complaining that I was shouting. Asked me what punishment I would like and I have no idea. Dh spoke to ds very gently saying his behaviour was wrong, ds said it wasn't and it was my fault. Ds then went to get all my devices so dh followed him and trod in his foot in the scramble )ds knocking stuff down and throwing things everywhere), ds then burst into brief angry tears claiming he was injured and the victim and retired to his room in high dudgeon. Dh gone off downstairs.
I'm on my own in my room. Ds has now gone downstairs and is shouting at dh again.
We have a dd, 16, who was the one who asked me to get ds off the computer in the first place as she had loads of A Level homework to do. I hate that she is growing up with this. She is less physically vulnerable than me as stronger and good at martial arts but she should not be having to potentially feel threatened by her younger brother. Obviously mentally this is shit for her.
And yes, dh is very abusive. Screamed in my face from a foot away in the car before Xmas that he hated me, in front of ds (because I had suggested to some friends they could come over before Xmas and he interpreted it as meaning he couldn't put up his decorations when he wanted and that this was therefore 'ruining his Xmas'. 
When my DF passed away just over a year ago, dh went pretty much AWOL, for the couple of months afterwards, he spoke to me for no more than 5 minutes a day and even when I pleaded and made it clear how important it was to talk about my DF, he would go out of his way to avoid me and avoid talking to me. 
He regularly puts me down (loudly) in front of dcs, suggested recently in front of the dcs that I was making up the racism (I am ethnic minority) I and my family have personally experienced and demanded 'evidence' of it, as though I was in court - the opposite of sympathetic (and horrific as it is denying the racism his own dcs are also likely to suffer and have already suffered a little). He did this even though he knows I am only in the UK as my family fled here because of genocide in their country of origin due to their ethnicity.
He also controls the finances so I have to ask him for small amounts of money and take on debt to be able to get by (we have lots of debt, nearly all in my name, even though I was the one until recently with no regular income, only freelance work). I recently took on a full-time job but haven't been paid yet. I'd leave tonight but would be sleeping on a park bench as I have literally a tenner I can access.
There's more. I should have left a long time ago but couldn't afford to. Is it too late to help ds too? I know that he is testing us, by being as much of an utter little shit as possible to see if we care or not. But I have to balance that with a right not to be assaulted in my own home and shouted at. Read something recently that made me realise that ds behaves like this because he can and because he gets lots of power out of it - he gets to use the computer when he shouldn't and throw his weight around. A couple of weeks ago, ds shouted at me while I was trying to work (working from home one day a week in a brand new job I'd only taken on in order to pay for stuff he wanted) until I cried. As soon as I burst into tears, he stopped shouting, said 'Good', with the utmost satisfaction and slammed the door shut. He told me he only pretends to be nice to get what he wants. I don't know if that is true or not but hard to trust him.
Had enough. I've held fire on the police after reading the above but had told him I would call the police unless he makes amends so he will continue to think he can act with impunity. If I had any more money or anywhere I could go (can't tell family or friends), I'd leave tonight.
Should be paid in under 2 weeks. Will leave then. Can't do this any more. Don't know what to do about dd as she will want to stay here (nice house, I couldn't afford anything like this).
Ds kicking doors and shouting abuse currently. My heart is breaking.