1. No. getting rid of her is not difficult provided you can establish your allegation with supportive evidence that she has been acting cruelly with all of you for long,
2. Collect the said evidence by audio/video recording her conversations particularly her abuses and threats of filing false complaints u/s 498A of IPC,
3. Do not worry about any arrest since as per last Supreme Court order, police has been directed not to make any arrest against any 498A complaint without conducting an investigation,
4. Is your brother staying with his parents in the same house? In whose name the title of the house stands?
5. If the title of the house stands in the name of your parents then ask your brother to separate himself from his parents and take up a rented house showing some reason to his wife like transfer,
6. Otherwise, your SIL will not leave your parents house and keep on creating nuisance for your parents,
7. Once your brother takes up a rented house and moves out with your SIL, let not your parents allow her to enter their house ever as a precaution. Once she enters the house, she won't leave it,
8. After taking up the rented house, your brother can file a divorce petition on the ground of cruelty and before that he should lodge a complaint against his wife for her cruel acts,
9. Your brother should be prepared to pay maintenance for her since once the divorce suit is filed, she will file a petition u/s24 of HMA, claiming interim maintenance which may go up to an amount in between 1/5th to 1/3rd of his monhly net income,
10. As a long drawn litigation policy, your brother should book a flat and pay for the EMIs for which his monthl income will be reduced accordingly.