Anyone go through this?

I am going through a custody battle and right now i have temp full legal and physical custody. My sons are 4 and 2. And my daughter is 8 weeks old. My 4 year old has a zoom meeting with their attorney tomorrow im freaking out. Idk what expect. Im nervous hes going to say something wrong that lessens my chance of getting permanent custody. Theres some issues I have brought up to the children's attorney like my concerns. So im not sure what to expect anyone give any tips or insight? Will I be able to sit with him??

Before anyone assumes im not wanting their father in their life I do. Hes just an emotional and verbal abuser. He abuses our animals and has laid a hand a few times on our children as well. He laughs at them when they get hurt and our son tells me all the things he says about me to make me look bad "this is my fault" so before anyone assumes please don't judge that I am just trying to protect our children as much as I can. I want their father in their life but in a healthy way.