Huge MIL issues

So I am 17. I got pregnant at 16 and me and my husband had a shot gum wedding. I don't feel like I can call her a monster in law because while his mother is mean to me how she is to him is on a whole nother level. She was very abusive. Physical and emotional. He has scars on his body from abuse that happened when he was 5. His dad lived him but was mentally ill and couldn't get custody. His dad says.commit suicide and she rubs it in his face. Our son is.4 weeks old and my husband has been making excuses to her to keep her away because he is honestly scared of his mom. I'm not though. We live with my parents and my husband has been in the bathroom crying the past 20 minutes. Here's there convo

Edit: The grandparents "rights" in our state she would have to prove she has a bond with the child, she doesn't and that her being in the life is its best interests. I've seen grandparents lose the case just for having texts calling the DIL a bitch. What do you think these texts will do?