She is 80 years old with Dementia with Lewy Bodies. Currently in a Nursing home. She is dangerous and has tried to take her own life 3 or 4 times that i know of. I sometimes come in fromoutside and fing her walking the house with nothing but panties and a carving knife. she has forgot I am her son and wants tohave sex with me. I told her we cant becuase its wrong I am her son and she is my mother. She replied "you should have never said that, you gonna regret that". In 20 days her Medicare will run out and one of my two sisters will remove her and take her home either to her house or my house, My other sister is with me and believed she needs to be in a nursing home. I have POA. I am her primary care giver. The doctor will sign a letter that she cant make competent desicions,
Depending on the wording of your POA you may well be able to direct her care now. Care facilities will probably accept your POA along with a letter confirming her incompetence from her doc to cover their liability.
Find a good memory care facility and ask what they require. Guardianship will require an examination of your mother, a hearing then a ruling by a judge. I doubt you're going to have to go through this given the advanced state of your mothers dementia.