Going through this exact same scenario right now, POA and elder abuse are areas where penalties are seriously lacking. I'm grateful that due to MMM, I was able to fight a very expensive legal battle to gain control of what I could, and hopefully by mid year I'll be able to get Mom out of the Medicaid NH she's in right now, assuming she survives this whole ordeal.
College educated sibling is lazy and likely has some mental issues, drained Mom's assets of somewhere between $300-$500k in a few years, to fund lifestyle. Designer goods and phone psychics were the notable items from discovery documents, but the majority was just death by a thousand cuts, $20 here and $30 there, adds up fast.
Once everything is wrapped up, I'll create a post with all the gory details and the many things I learned through this process. It's QUITE the education, and very demoralizing.