Can my sister and brother keep me from seeing my 86 year old mother?

I am 56 years old and never had a problem with the law. I had a financial problem and was sentenced to 16 months in prison. Prior to leaving my mother and I had a terrific relationship. She had been diagnosed with dimensia but it was in the early stages. I called her upon my release and found out that after 30 years she no longer lives in her home and her phone number is no longer working. She never used a cell phone so I cannot access her that way. I tried to reach out to my sister and brother with no success. It gets worse. While I was away, my brother and sister filed motions to have me removed along with my mother from her estate. This was a Trust set up by my dad who passed away, 17 years ago that my siblings found out about. I know that they are only concerned about her money. I also believe that my sister has Power of Attorney. I do not believe that either of them have her best interest at heart. I reached to some of her friends and family members but either they do not know or have told me that they do not want to get in the middle of this family issue. My prison sentence was a white collar financial situation AND I paid back the majority of the money prior to sentencing. I believe that she is unaware that I am out and trying to see her to make sure that she is okay. Do I have rights? Can they do this? There is more but this is the basic situation. Please let me know if anyone can help me understand what I can do to see her and how I can locate her.