You seem to be confusing legality with ethics, or perhaps morality.
But in any case, since you're convinced he was fully mentally competent, then what was illegal? He must have fully understood that the power of attorney paperwork he signed was transferring full financial control. And it'd be hard to argue that the money was not managed in his best interests.
So if a fully competent adult willingly signs away financial decisions for his money, and those decisions are made, what problem do you have with it? After all, it was his decision to sign the paperwork, if a grown man wants to hand over financial control to someone else, why should anyone stand in his way? Just like in your scenario, if a grown man wants to hand over his life savings to anyone that can tell a sad story, why should anyone stand in his way?
Regardless of what arguments were made to persuade him that signing the paperwork was a good idea, the details were all clearly spelled out in the paperwork.
But in any case, since you're convinced he was fully mentally competent, then what was illegal? He must have fully understood that the power of attorney paperwork he signed was transferring full financial control. And it'd be hard to argue that the money was not managed in his best interests.
So if a fully competent adult willingly signs away financial decisions for his money, and those decisions are made, what problem do you have with it? After all, it was his decision to sign the paperwork, if a grown man wants to hand over financial control to someone else, why should anyone stand in his way? Just like in your scenario, if a grown man wants to hand over his life savings to anyone that can tell a sad story, why should anyone stand in his way?
Regardless of what arguments were made to persuade him that signing the paperwork was a good idea, the details were all clearly spelled out in the paperwork.