The older sister has POA of medical and finances. According to the eldest sister my younger sister has dementia. The younger sister suffered a bad head injury quiet some time ago and as everyone knows with these injuries people change. Fast forward some 23 years or more now the older sister has control over her and I believe she is being abused physically emotionally and definitely financially. What can I do to help? I'm willing to become the care taker but the older sister does not want to let go. How can I find out if what she has is legal? Cant afford a huge legal battle but willing to fight for what is right for my younger sister.
If your older sister has been your younger sister's caregiver for more than two decades, it would be understandable (and merit sympathy) if your older sister needs help just as much as the younger one. That's a heck of a burden to have carried for so long. Your older sister might be reluctant to let go for all kinds of reasons, some with good intentions (e.g. believing that no one else could be equal to the task) and others more worrying (e.g. being terrified that abuses might come to light, which could also be combined with searing guilt).
But untangling it is a tricky, delicate and complex task, and you will need expert help. How closely involved are you with both of them as things stand? And how did it come about that Older Sister assumed responsibility for Younger Sister - were decisions made by your parents, for example?