What should my sister-in-law do to bully her elder sister with her in-laws protection?

Sister-in-law bullied elder sister with her in-laws protection. I suggest you try the following methods:

1. Communicate with your elder sister-in-law privately, express your concern and understanding for her, and tell her your support and protection for her.

2. Communicate with your in-laws, tell them your care and support for your sister, and hope that they can treat every family member fairly.

3. If the above methods can't solve the problem, you can consider seeking help from other family members, such as asking family counselors or psychologists to intervene and assist. No matter which way is adopted, we should remain calm and rational, respect the feelings and rights of each family member and seek a harmonious solution to the problem.