I faced this too with my Mom's rejection and denial of me to her kept kids. I was asked by a sister, 'why should I believe you- a stranger- over my mother'? I had one sib who was willing to go to the agency with me to verify I had found the right family. CHS wanted to play MORE head games. Refused to confirm or deny directly...but bro could write a letter for them to place in my files, and then I could call and ask if there was anything new in my file. ??!? It absolved them of any accountability. Jerks
I had held back sharing my non-Id with sibs. I finally sent them a copy and a couple of pics of myself. Her background info matched perfectly and the pics were proof in the pudding. I hope you are able to put yourself out to the sibs before moms condition worsens. My mom held back in fear of what her kids would think about her. As soon as she was confident that they still loved her, she opened up to meeting me. Good luck.