Why my sister don't want her child?

My older sister has a daughter. She no longer has here daughter as of June 2010. Still. I have heard horror stories about where my niece is residing. There was a DCF case that took place and my sister lost custody of her daughter due to child abuse and neglect. She had steps to complete and did nothing. It has been 7 years since me, my mother, and my younger sister have seen my niece. The lies that have been told, the no guidance, the manipulations that has taken place, has given my niece an outlook on us as we didnt want her. She was taken away at the age of 10/11 and I haven’t seen her since that day. She is now 17 yrs. old with a lifestyle of what has been done to her. I am not here to judge her, but, I want my niece to have the life that she wanted before this horrific dream came. I am CONCERNED dramatically for my niece and my older sister. My older sister has a demeanor that is very abnormal to a parent that wants her child back. My older sister has degraded my niece, she has fought my niece, and she has told my niece a bunch of lies about me and her grandmother. We, I, am to the bottom of the pool. I need to know what, if any, if my older sister is on anything. My niece, I did find after I searched for years. To see how she has grown, has made all tears reappear. The language she uses, that I believe she is angry, the dresscode she has, could have something to do with the home life style of the person that has custody of her. I, am so upset, frustrated, annoyed, and pissed, that the mother, the people that my niece stays with, SHE DONT NEED TO BE THERE. Based on Florida Law, I, as an aunt, DONT HAVE ANY RIGHTS AT ALL. Please someone give me advice, please someone help me out on what I may do. If anything.