DS1 (12) has just started boarding at OCC ss and all seems to be going well.
The problem is when he comes home. Not so much with me or DH but with DS2 (7).
DS2 has 'blossomed' since DS1 started boarding and says that he much prefers it when DS1 is not here 
Last weekend was a nightmare. DS1 said to DH 'I never thought that I would say this but it turns out that you are the only one that likes me' 
DS1 wants to immediately re-establish total and absolute control (not surprisingly) but DS2 does not like being ordered around and being absolutely powerless. So DS2 wants to play on Minecraft but DS1 does not want him to, DS1 takes over control of the computer and starts doing things in DS1's world that DS1 does not want him to do. When DS2 does not do what DS1 wants then DS2 will amuse himself by winding DS2 up - constant critical commentary, constantly calling him bumhead or Mr Poo or stressy pants until he loses his temper and physically attacks him.
When DS2 is upset at 7.30 on a Saturday morning you know its going to be a hard day. Things break down if I am out of the room for longer than a couple of minutes. I can't send DS1 anywhere or make him stay anywhere, if DS2 sticks with me, DS1 will closely follow him and copy all his actions/words.
I seem to have lost my extreme parenting powers over-night and actually asked him plaintively 'can't you see when people have had enough?' Well, duh, no.
I know that DS1 is having a difficult time atm but he is still being a monumental pita.
At the same time, I feel huge guilt over neglecting DS2 and I feel half-bereaved because DS1 has 'left home'.
Last weekend DH took them out for a bike ride - nightmare before they left but once in public DS1 becomes ultra-compliant and he and DS2 get on well together. Trouble is, by that time I had done a mornings policing and desperately needed a break and so I stayed home. So I get the crap time at home and not the good times.
DS1 goes back to school, I think 'thank god' but then feel terrible all week that I can't spend good time with him. He has been off school since Sept so I we have got used to hanging out. I miss him. I look forward to seeing him. But when he comes home it all goes wrong and he is gone again before I can fix it.
We are planning whole family activities this weekend but still need strategies for how to get through time at home.
Any advice gratefully received.