I've been reading alot about disengagement but I currently can't do that. When ss12 comes round he causes arguments between my husband and I usually by shit stirring or being so disrespectful to me that the house ends up being tense.

Everytime he's here I end up locking myself in the bedroom to avoid confrontation or any form of encounter with him the kid is a brat! 

What makes it worse is his demon mum allows him to misbehave and regardless what DH says he only behaves when there are others around.