I have medical POA and my brother has financial POA. Any advice?

Unless I'm wrong, I believe the medical POA makes the care related decisions like assisted living and the durable POA makes sure things are paid for from the persons's resources. Your brother has no right to not pay the increase in rent and if he keeps this up, your mother will end up being kicked out. It is wonderful that the care she is getting is great. Just because the siblings think the rate is to high is not a good reason for going to another place that is cheaper. It may cost less and it may care less. Ya'll need to make an informed decision about this and investigate your options instead of making a decision on finances alone. Are finances even an issue at this time? Do your siblings understand that she needs more care and that in itself is going to cost more? Has your brother talked with the doctor and heard his explanation of why it would be a bad idea to move her?

You make her care decisions. Brother arranges to pay for them.

I suppose you could investigate the less expensive place, and if it is seems to have care quality as high as where Mom is now, then the main issue to discuss is the problem of moving her and what that might do to her health status. If the quality isn't as high, then that is what needs to be discussed.

Is Mother about to run out of money? How soon, at this current care center? You do have to be aware of the financial realities, too. Would the place she is in accept Medicaid when she is completely out of funds? Many assisted living places that don't accept Medicaid for new residents do for residents who have been there a certain length of time (often 2 or 3 years). That is worth finding out.

Are your siblings actively involved in Mom's care?

Very tough situ to be in. The person with medical gets to decide where the person resides. The financial person has a duty to pay the bill. If the bill not paid, then the fin POA would be seen as not performing their duty and APS could get involved. However if med POA is choosing housing too eexpensive you're asking for trouble, so you better have a good understanding of why fin POA thinks the current bill is too high. Nobody knows how long an elderly person will live.....7 yrs already of AL likely has cost a huge amount of money. I have a neighbor whose mom is 101 and still going strong.......spend the money wisely, or your mom could be on Medicaid and not many choices.

Get a court order forcing the POA to pay the bills or be removed.

Well it might be better (and cheaper) before last resort "get a court order" to write your questions & concerns in a letter, ask for a written response within 5 days, and mail it certified mail, to the FinPOA. That way he has an opportunity to provide documentation as to why a move is required, and if he refuses to comply with your rational questions, THEN you go to court and the judge will see you have already attempted to resolve in an amicable manner. If he doesn't comply with your request, send a 2nd request and ramp it up a bit, include language like "this is my 2nd request, if I don't hear back from you I will have to seek a court hearing" and that might save your mom (and maybe you) a whole lot of legal fees. My point is, be nice, but firm, and avoid lawyers/courts if at all possible. It's not glamorous like The Good Wife. It's extremely expensive and may not obtain your desired result.