I'm really concerned about my children

I have 3 children age 12,10 and 4
My 10 & 12 year old have the same father there is a custody order in place for them (they are not happy with this to start with)
He constantly tells them their opinions do not matter until they turn 18 and they have no say in anything he asks them if they want to do things then goes against their decision (because he's The adult) so the new thing is he has bought a lease on a pub (it has no living accommodation) he has told the children they will be doing the table service of taking drinks to the tables, the children do not want to work in this pub, my 12 nearly 13 year old says this was his choice why do I have to work in it? He's told them they have to wear a uniform and be part of the team, everywhere I've searched solicitors I've spoken to say it's illegal, I cannot even speak with him as everything is turned round to be my fault, if the domestic violence laws were changed before 2015 I would have had him charged, but it's too late and not an option all I can do now is go back to court and try change this order, I was wondering if anyone had any advice I could give my children to help them through this till then
Thank you