[quote Unsure33]@MrsFin
She had another baby with the unsavoury character who is off the scene through a court order so can’t afford to work at the moment . I tried to get her to look at benefits and childcare but she has not done that .[/quote]
If she can't even be bothered to enquire about benefits and childcare for the one dc she has with her full time, and is happy to settle for an uncertain housing situation, living off others and 'doesn't want to work', what on earth makes you think she has the other dc's best interests at HEART? She's already proven that she can't make the best decisions about people she invites into their lives by having a baby with an 'unsavory character' who is court-ordered out of her/their lives - this will not go in her favour if she challenges the dad over school places/changes to the residency.
Will she be bothered to get their uniforms ready for school every morning? Sort out a packed lunch or make sure their lunch account is topped up? Will she make sure they have PE kit ready on the right day, and £1 for the PTA event? Will she sit and read with them every night? Help them with homework, projects, and revise for tests?
That's before you even think about the domestic situation.
It's not fair to expect one parent to do all the drudge and the other get all weekends and holidays. From either perspective.
As pp have said, the children have rights, the parents have responsibilities.
From what you've posted, it doesn't sound like you're concerned her ex is 'throwing his weight around' and extending some sort of domestic control/abuse over her - whilst I know this happens, she sounds INCREDIBLY passive yet expects that just because she is the female parent, that the dc should reside with her. Sometimes, often, this just isn't the case, and she needs to do what is best for the dc. Her 'supportive family' need to give her a kick up the bum to get into a better position to provide for her kids.
I think this is one situation where the dc will be better off with their dad being RP.
Remember op you are only hearing her side of the story and it's not looking good. Imagine what the real truth is?