Stars, another question for WA that you can ask is what steps could you take to prevent your H from taking showing up at the school and taking the children with him. They will have undoubtedly had experience of dealing with this senario before and will be able to tell you where you stand legally.
I know you are really concerned for your children, ds in particular but the disruption will only be for a very short time and you will have the rest of your lives to settle into a new routine. I urge you to consider the disruption your children are already enduring, due to their father's unpredictable behaviour and violent mood swings, never knowing when he will be home, what he will be like, will he shout at mummy? will he be nice daddy or will he be grumpy? Life must be pretty unsettled for them already stars, and it's all down to him.
The one consistant, stable, nurturing influence they have in their lives though stars is YOU !!! You are always there for them, whenever they need you. I bet it's you who goes to them if they wake in the night, we already know it's you who takes them to all their appointments, who runs their day to day lives.
NONE of that is going to change Stars, the place you do it all in will but the most important part of your children's lives is YOU !!!
Of course they love their Dad, and of course they need him too, but at the moment he is putting his own needs above everyone and everything else and until HE changes that, you have to do what you have to do.
I hope you and Dread have a lovely meet up tomorrow, eat LOADS of biscuits for me, I've just had a gasrtic band op so am a biscuit free zone!