How do you prove child manipulation/brainwashing by their mom?

Girls (2) are 9 and 11, I, their father have joint custody and have been battling their mom for years to get her to work together with me and can't. She's a control freak at home and school and needs to stop brainwashing and manipulating our daughters. I would love to go to court and get them away from this nightmare situation but not sure how to "prove" it in court.