How do I stop other family members from financially exploiting my mother?

Thank you everyone. You are correct she is incompetent. I only sent my mother from California to Texas. The younger sister sent her to Minnesota and has been there for months. I let it go for s minute because this is her last of her years to see family. I reported to APS in Minnesota for neglect and tried doing abduction. The investigator saw my mother and said she was well. I was furious because my concern was she had doctors appointments that she did not go to. Then I reported financial exploitation, illness/cognitive and money & property. I am now waiting for that response. I don’t get it, if I’m dpoa how can someone else change her address, bank accounts , etc.....

Assuming your mother has dementia (which is the ONLY way you would have any POA authority over her money, by the way,) you must find all checks, debit cards and credit cards and take them. I had to do this with my mother. I literally "stole" them right under her nose. (She had written a check to the hairdresser for $800. instead of $80.!) She was also charging things that she didn't need-a ceiling fan cleaner but didn't have a ceiling fan.
It is your duty as POA to protect her from everyone who could get their mits on her money and also protect her from herself.

I would also throw the fear of God into your family members by saying they will be prosecuted for having coerced a demented loved one into giving them money. Tell them they could serve jail time!

Why is she traveling around the country with Alzheimer's anyway?

Take away any bank information so she will not be able to call them or give them an account number. Make sure your name is on her accounts and alert the bank as to her dementia.

I fought with mother's bank to close down her credit card. They had a copy of her doctors' statement of Alzheimer's AND my POA. Only thing that got them to cooperate was I told them THEY would be responsible any charges as of my notification. They closed it within 1 week.

Gotta' play hard ball sometimes.

I think rempleo meant to write "incompetent"?

In my state, Social Services is useless in trying to save old people from exploitation. There appears to be no way to stop the exploitation w/o engaging an attorney. If you do this, be sure to get one who specializes in "elder law."

It's a pity you didn't set the bank accounts up to require signatures from both of you, but too late now.

If you figure out how to solve this problem satisfactorily, I will read the solution eagerly. It might help someone I know who is being taken advantage of.

One part of your post says your mother is competent and then you say she's Stage 6 Alzheimers, so, I'm confused. I also don't understand why someone with Stage 6 Alzherimers would be traveling around to different states. I would think she would be in one place receiving care. I would imagine that insurance of any kind would be complicated if she's living in different states.

I would consult with an Elder Law attorney to get the law on your DPOA. If mother is competent, how does the DPOA come into play? I might also ask about reporting the events to law enforcement, if she isn't competent. You say that one investigation with social services is under way about a fall. Do they know all that's going on? Are these financial things legit. I'd be very suspicious and have it checked out.