Do I need something called Petition for Guardian? What can I do??????

If Mom has been formally diagnosed with Dementia, your POA should be enough to place her. I would have her checked for an UTI. There's meds to help with her aggressiveness.

Yes, you can place her in a nursing home with a POA if it's in her best interests and she isn't competent to make that decision.

It'd be a good idea to get a letter stating her competency from her doctor, but you don't need guardianship.

I'm sorry you're going through this with your mother & her progressing dementia. She would have to agree to go into a Memory Care AL or a Skilled Nursing Facility in order for you to be able to place her there; POA alone is not enough to be able to do so against her will. She could walk out, but not literally because the doors are kept locked, but she could insist on getting out of the place and call a lawyer to help facilitate it, I suppose (depending on how advanced her dementia is). So yes, you would need guardianship to place her in managed care against her will.

Have you tried talking to mother to see how she feels about going into managed care? If she's against it, go speak to an Elder Care attorney for guidance on getting guardianship over mother.

Wishing you the best of luck with a difficult situation. My mother is 95 next week with advanced dementia & living in Memory Care AL since June 2019. I had both of my parents in AL since 2014 and Independent Senior Living since 2011 b/c living with me was never an option, as I knew it would be a bad idea. I hope you can remedy this situation; I feel for you.