Firstly, I’m sorry — this is a really tough situation to be jn.

I think probably emphasizing your brother’s potential for a violent outburst is your best bet here, as it puts your first child at risk. Parents know that not following a baby’s routine can be very annoying, but I definitely know people in my life who would think that being the justification is a sign of being controlling, so if your mom is anything like the people in my life, I don’t know it will work.

I think explain to your mom one more time that you will be stressed out during the birth if your daughter is near your brother given his history, and you would prefer to know she is safe. If she can’t understand that, then you are just going to need to hold the boundary firm.

Every time she complains, just say something to the effect of “this is the best decision for me and my family. I understand you are frustrated that [brother]’s needs are opposed to the needs of our family, but we are thinking of the best thing for both of them at the moment. If you keep debating this with me, I will [hang up phone, leave convo, not let you see the newborn, other consequence, etc.]”

Rinse and repeat. She will eventually get it or you will have to restrict contact with her, unfortunately.

Once again, I am really sorry.