To follow somewhat from nrb80's excellent post....
Sometimes it's not about wanting the inheritance vs. charity. My parents and their siblings had to keep their parents from giving away money so they would be able to afford the nursing home. It was $6,000 per person, per month. For the bed and food. Not for pills, not for trips when they could take them...good nursing homes are expensive. My dad's mom lived 2 years there, his dad 3 years. It adds up.
So in order to make sure they could STAY there for as long as possible/as long as needed, they had to keep them from giving away money to scammers. My mom's dad had an old girlfriend that suddenly showed up and wanted to get money from him. He thought she was fine. We knew better. Hence why on his main accounts my mother was POA, and he couldn't draw money without her signature as well. My dad's parents (and his aunt, my godmother) had things stolen from their houses by home health aides.
There are many many wonderful caregivers out there. Sadly, there are also a boatload of scammers. My parents took care of me when I was growing up, and my job will be to take care of them when they're old. And because they know I love them, they know I will do what's best for them. Even if they don't like it very much.