Facebook Photo Removal Assistance

I need help getting a specific photograph taken down from someone else’s Facebook account. On that picture is my son of 10 months. I have strictly forbidden my son to be placed on Social media. When my husband contacted the person who made the post (his sister) and requested the picture to be removed, she simply said and I quote "I don't need your dumb wife's drama's", refused to take it down and placed a restriction, so I can't see the post anymore. I do have the legal authority to request its removal, as a mother and legal guardian to my son, but I’m unfamiliar with the most effective way to proceed through Facebook’s reporting, copyright/privacy, or court-order channels. The job focuses on: • Identifying the fastest, policy-compliant path to have the image removed (copyright claim, privacy violation, defamation complaint, or another applicable route). • Preparing any required documentation or takedown notices so they meet Facebook’s evidence standards. • Submitting the request and monitoring Facebook’s response until the picture is no longer publicly accessible. • Supplying me with clear, dated proof of removal once the process is complete. Experience with Facebook’s Copyright & Trademark Policy portal, privacy reporting tools, DMCA procedures, or legal takedowns is essential. If additional legal language or notarised statements are needed, please outline them at the outset so I can supply signatures promptly. Success is confirmed when the image is permanently removed or blocked for all users.