How can one enforce a POA when a sibling takes parent from home and the caregiver?

My husbands mother has dementia, she is 93 year old. We live 2 hours from her and she lives alone. She is not keeping her house clean and we don't think she is eating healthy meals, looks like mostly candy. She isn't taking her heart medication as directed, she feels she doesn't need to. She is very uncooperative when we mention getting help for her so she can live in her home. She has over drafted her account several times, which we have had to cover to the tune of over $3000.00. We tried to bring a person in to see if she would qualify for household assistance for home repairs if needed, she refused to speak to them. We do have financial and health POA's and my husband is on her accounts, how do we enforce the financial POA so she doesn't have control over her checking account to prevent the over drafts? We don't want to take her to court for guardianship if we don't have to.

correction "preserve their parent's assets for their inheritance *by* looking after the parent themselves"

If I understand it correctly the financial POA is responsible for - obviously the finances - seeing that mother's assets are used for her care. In my case (in Canada) the "health POA" is called a personal directive and the person named as the agent is responsible for making decisions on health matters and also includes where the person being cared for lives. If this is the case in the US, then the health care proxy has the authority to make that decision, if your mum is unable to make it herself. I think you need to document what is happening. The sib who took your mum to her home may find that it is too difficult a job and be willing to look at some alternatives. We have seen cases here where a sib or two wants to preserve their parent's assets for their inheritance but looking after the parent them selves.Have you any idea what the motives for this move are?
I agree that it would be ideal if you could find some common ground with your sibs. You state a concern that the sib who took your mother has never been able to care properly for her. You need to keep an eye on this for your mum's sake. Is you mum able or unable to make decisions for herself? You don't mention her health issues, her competence. Your caretaking sib may burn out and be willing to return your mum to her home to be taken care of by professionals. Good luck.

Just because one has a Financial POA doesn't necessarily mean they get what they want. Unless a court has found mom incompetent, whatever mom wants rules. As she's at one of her daughters' houses, it would appear that she wants to be there.

Financial POA should make funds available to the sister who has mom. Saving the cost of a professional live-in caretaker isn't small potatoes. Use some of that money to make sure your sister has what she needs.

And don't forget the main goal: to take good care of mom.

Pam Stegman nailed it, in my opinion. This is a family problem...probably of long-standing. There's really nothing practical you can do, in my opinion. Find a way to make it work. In the end, as long as mom is being taken care of, what difference does it make in whose home she lives?

You go to court. You argue before a Judge. The Judge sees that there is no agreement among the siblings, so he appoints an independent third party as her Guardian, who charges big fees and everyone hates the Guardian. Mom gets placed in a facility selected by the Guardian.
Sorry, but those are the facts. So work it out if you can.