This is a very dangerous situation. Your friend is terrified of what he’ll do if she leaves. I’m terrified of what he’ll do if she stays. She and her child are in danger. I think you should call child protective services. In most states, such calls can be anonymous. Our first obligation is to protect little kids who can’t protect themselves. Perhaps a visit from child protection will be the wake up call this couple needs. He won’t be able to blame her if the call came from someone else. She may get the message that she needs to get out of this situation before she or her child get hurt. You might also research where the nearest shelter for women escaping domestic violence is located so you can provide her with the information.
I understand why you might hesitate to take action. But think about how you will feel if in the next phone call you learn that it was the child, not the the floor that was shot.
I wish. You well.