How to Remove POA from Nursing Home in Mississppi?

Location: Mississippi. Background: A long time family friend has a brother who has power of attorney. Friend, who is in her 70's is on disability and lived on her brother's property in a separate dwelling for many years. Friend would do cleaning and petcare while brother was away, which was often.

A year ago friend began having issues with her leg that caused mobility issues. Coincidentally brother and his spouse had to move to a different state for treatment due to a terminal cancer diagnosis. Brother moved our friend to a retirement home "temporarily" for safety reasons. When she asks when she can leave (leg issue has resolved itself) she is told not to worry, just wait.

She has asked staff the same question and was told that she is there due to her dementia, which was news to her. She told them that she has never even been tested for dementia and asked to see her records, which has not happened. She plans to revisit the matter, but the issue of POA remains.

When she asked her brother about the dementia diagnosis he said not to challenge it because she will lose her disability. **Very important to note--over the past year he has given friend's car and home to a different relative. Friend was notified re: both after the fact and told not to worry, he'll replace the car. So the little money she receives (under false pretenses?) is largely going to this retirement home where she has no freedom to work on getting herself out.

I told her she should have the POA revoked, it just has to be notarized but she literally cannot physically do this without her brother's permission--and he will not agree to it. If anyone has advice I would be so grateful. I live several states away and am just trying to figure out how to help her. She's feeling pretty hopeless and defeated.