How can I find out about my parents' finances and assets when I have no money for legal fees?

My older sister who is 59 years old became Power of Attorney without telling my brother or me. Since her divorce about 25 years ago she has not been her same self. She hasn't had a steady job I years. She came home to my parents house, slept and stayed secluded in one of their bedrooms with the door locked. My brother and I know and believe she is depressed and emotionally damaged. We also believe she is in need of some serious counseling to face her emotional issues. My parents never put her put her out so she stayed and became and still is nonproductive. The only thing that seems to make her feel good is being able to handle their affairs and she's doing a sloppy job. Both of my parents are not able to take care of themselves and I am convinced that she is having some ulterior motives when it comes to their finances. I WANT TO KNOW WHAT'S GOING ON! It's aggravating to see her get away with murder right under our noses. What do you do or can you do when you have no money for legal fees