My father’s wife was seen abusing my father by several sources. He is in a nursing home. Why isn't she in jail?

There was an investigation and I think they could not substantiate it because my dad is afraid his wife will stop visiting him and would not say she did anything. She was actually trying to cause severe harm. Her visits are supervised though. Can she loose her pod and mpoa over him? Why didn’t she go to jail? Can my sister take over her mpoa and pod?