How can we contest a POA?

What does Grandma want?

S

Sounds like grandma picked the one she trusted to be POA. You can get a lawyer and try to prove in court that the POA is not acting in Grandma's best interest, but an argument that you don't want Grandma's assets going towards her care because you want them yourselves is not going to serve your case well.
You will have to prove that the PoA is stealing from Grandma or not using Grandma's money to take care of her properly.
Then, the court (If Grandma is incompetent) would possibly appoint a guardian for her.
If Grandma is competent, she can revoke the PoA, but from the information you gave, it sounds like that is not the case.

Nisha,
It depends...
How old is gram and does the person with POA have
FINANCIAL  POA AND
 a POA for Medical Care decisions?  There is a difference.

After only 90 days, someone it appears is not on top of the financials to start with.
So come back for the wealth of information these caregivers can discuss with you if you provide more information.
Dr. Kernisan is my favorite geriatric care specialist whom I read all the time!

The OP appears to have left the building. We don't have enough info to answer the question except to say, "It depends..."

I agree, sounds like POA Is filing for Medicaid. You don't say how old GMom is. The stroke my have been a dibilitating one and GM needs more care than POA can give. You need to have a family meeting and get the particulars. Maybe one of u will care for her. POA doesn't mean she has to physically care for her.

You cannot contest a POA. The only thing you can do is offer a better solution. Nursing homes don't want to keep people who are well. It sounds like she went from a rehab unit to a long term unit, perhaps because she has not gotten well enough to go home. (Fyi, people in long term units can still get physical therapy.) It also sounds like you're concerned the nursing home will take her money, but as jeannegibbs noted, her money will be required for her care regardless. If your concern is that the nursing home is a dump, or you're unhappy with the care she's receiving (you visit regularly, right?) then you can research other nursing homes in your area, tour them, and find a better option. If you just don't want your loved one in a nursing home, that's understandable. But then you need to come up with a great alternative for your grandmother to get the same level of care the nursing home provides, and that will be tough. Good luck.

If this elder does not have or need guardianship, I would go ahead and go pick her up and bring her back home if she is able to live at home. Another thing I would do is call my state bar association and tell them what's going on. I would also overturn the POA and have this particular one removed. What you may want to do is have an eldercare lawyer step in and help this particular elder protect her assets before the state has a chance to grab them. 

What you may explore is a TOD account for the home and possibly even the car. If there is a TOD in place, the state can't grab those assets. This is what my bio dad did with his house and no one could touch it

You don't mention if the elder has applied for Medicaid. That is a big missing puzzle piece.

Why specifically is everyone but the POA against this?

As @jeannegibbs pointed out, the POA usually doesn't have to answer to others in the family. Exactly how the POA can handle his/her duties usually depends on state law and on whatever is specified in the POA or trust documents. Some older people have also specified what they want in an advance directive, but it can be a lot of work to get others (POA, doctors, etc) to follow the directives, if there are any.

If you have concerns about the POA's actions and you think there is actual fraud or abuse going on, you can try calling Adult Protective Services.

Otherwise, I think you would have to consult an elder law attorney in your state. They would know what your options are...including under which circumstances you might have a case for going to court and requesting guardianship. Good luck!

You only mention the financial aspects -- lien on house, etc. Are there any other reasons that the nursing home isn't a suitable choice?

What is Gram's condition? Some people recover remarkably well, and others lose ability to do activities of daily living and cognitive reasoning ability. I assume you have been visiting Gram regularly in rehab. What is her situation? Can she walk unaided? Being in rehab 90 days might indicate that she hasn't regained her strength -- what have you noticed? Is one side of her body paralyzed?

If she did go home, could she afford in-home help?

People name a POA so that one person has the responsibility of making decisions. It is not done by committee and it is not a democracy. The POA must act in the best interests of the principal as he or she sees it. Many POAs would want to discuss it with other loved ones, but that is not required, and the POA does not have to be guided by the opinions of others. (Being POA is a heavy responsibility.)

Was Gram in her right mind when she named the POA? Is POA taking financial advantage of Gram? Abusing her in any way? People are allowed (encouraged) to arrange for their own spokesperson and it would take considerable proof of wrongdoing to set aside Gram's decision.

On Medicaid, Gram is allowed to own a house and one car. All of her personal property, (furniture, linens, that lovely set of tea towels her mother embroidered, etc.) is exempt from Medicaid's interest. She can set aside money for her final expenses (funeral etc). She is expected to use her own funds for her care, as far as they will go. This is exactly would would have to happen if she went home. She could cash in her insurance to pay for in-home care, then perhaps sell her house and use the proceeds to pay for a smaller, more manageable place, etc. etc.

Any way you look at it, a person who has a serious health problem in their later years is highly unlikely to have anything to leave to heirs, if that is part of your concern.

BTW, how old is Gram?

Is there 24/7 care lined up outside the NH? From what you wrote, I assume the POA has applied for Medicaid. We need a lot more information -- mainly who is going to be responsible for the caregiving and why the POA doesn't think it a good idea.