I am also glad to read that even if not ideal or sustainable, you and the child are at your parents.
For me, it was hard to keep realistic thoughts in my head. I tried to play out each scenario a thousand different ways. The "If he does this, then ..." game until I made myself sick. I also learned along the way that my xah kept me engaged by his "threats" financially, emotionally, about the children ... at the end of the day I can safely say everything out of his mouth is bs and doesn't deserve to take up space in my head. I am slowly learning to trust real actions not words. Sometimes the threats were scary (especially if he felt cornered), please document to appropriate authorities if that happens to you (I did not at first) and document everything in a journal. If at all possible, have any communication with him regarding the divorce or the child to email or text. Keep making the next right (and safe) decision for yourself and the child regardless of what he says he is going to do. I say his money for an attorney is trying to scare you into not fighting him.
I might have missed it, are you able to go to any face to face al anon or nar-anon meetings?