3 month old and divorce

I live in Pennsylvania and we have a 3 month old My husband and I are getting a divorce. There was no cheating involved, but he said he would use my mental health as a way to get full custody to my baby boy. My question is has anyone gone through this?? Will he get full custody? I don’t want to go through the courts but he starts work at 4am Monday through Friday, he can’t take care of our baby boy. Will mental health affect that?