Are you working for Courtney Love?
BTW, this is totally fucked up, and you know it. Have you seen her pinch or kick the children? Do you think her language toward them is abusive?
You are a mandatory reporter. You need to think carefully about whether you need to tell someone about her. She may think she's funny, but being outrageous with your punk rock friends who "get" you and are also outrageous, and being abusive to your staff and children are two very different things. If she can't tell the difference, then someone needs to say something!
Also, why are you agreeing to keep secrets? People do that for a reason -- which parent is the dangerous one? Does DB not believe in medical care?