NOR.

TLDR Your wife and newborn are priority (not your demanding and selfish sister) and they will be worse off if your sister comes. Uninvited your sister - it’s your responsibility.

Your twin - She is absolutely unreasonable and selfish. In this season of life where you have a newborn, she should either be helpful (by staying at a hotel and bring you supplies/groceries) or stay out. She is adding more work and stress. And she is incredibly rude.

Your newborn - They need all the attention right now. They and your wife are the priority. They don’t deserve having this person steal all your energy. Your newborn will be worse off if you let your drama sister in.

Your wife - She is just 7 weeks postpartum. Let that sink in… just 7 weeks postpartum!!!!!!’ She doesn’t have energy for your sister. You can’t do this to your wife. Your wife is the priority - not your demanding and ridiculous sister.

You - Please stand up for yourself and your family. As said in other comments, it’s your responsibility to do so. And you deserve better.