And in that case, it seemed like her holding company was abusing her.
So invoking power-of-attorney over someone isn't always the solution to their mental health. Its an extreme move, and I'm really not sure if its designed to be used in the typical mental-health case.
Its not like the mentally ill are suddenly incapable of performing useful work, or unable to watch over themselves. They just have... delusions, bad memory, swings of mood, terrible sleeping habits, etc. etc. They need help, not someone walking in and stealing their money / taking their house / losing all sense of agency all together.
Mental health is... difficult, but livable. Extreme actions like invoking power-of-attorney probably makes things worse in more situations IMO.