Hi, I have a question regarding custody of my daughter.

My husband passed away 4 years ago and my mother in law asked me to leave the house with my daughter when she was just 3years old. I've taken care of her till last year when my mother in law fell ill with cancer and recovered She reached me and said she wants to spend her last days with her only grandchild as she don't have any other She have one more son who is well settled on US and he paid for my daughter's education last year and as I'm a working mom and due to covid I had to leave my daughter with my mil for safety reasons. Now I want my daughter to spend time.e with me as covid situation I'd getting better. But my brother in law is threatening me to file a custody case stating they have all the money and means to give her a better life and being with me will spoil her future They are not letting me meet her or to get her to my place. They are saying they have all the proof that I'm financially unstable and want my daughter to be with them. I'm still her legal guardian,