POA has denied me access to my mother's room at the nursing center. Can this be legal?

Sounds like you may have some of these outlaw people in your life like I had, you need to find out who the lawyer is or was that drafted that document and get with him asap. because if someone is doing the flim flam on you it must be corrected like yesterday.

I know yall dont usually like hearing about the Outlaws of life but I too have a handfull of them in my mix here. one is my own son whom is not my own son come to find out, but anyways they have gone as far as to file false crime reports to have us arrested then tried to move in my ex wife and the plan was in motion, take moms meds away send her to hospital due to meds lost, my ex and ex son take over home viola. that is messed up but it almost happened there has been 3 diffferenrt attempts on my life by my own son just for that purpose. anyways dont say it can never happen
heck if it can happen to little ole me it can happen to anyone

CNA not helping you disrespect and violate the persons pt. rights they are being paid to care for.
Refusing to help you ... Help the CLIENT to reposition in chair sliding out of... client being injured because CNA FAILURE on facility to properly position/reposition in safe manner Client in chair. It is NOT your Responsibility to Pick mother the client up when sliding down in a chair. Nursinghome staff responsible.
I would talk with Director of Facility regarding CNA neglecting safely repositioning for safety your mother in chair.
ACHA can be contacted as concern and website of facility has comment place also concerns grievance forms or a letter from you with these concerns written sent to DON and Director of Facility and Parent corp. and Licensing Accreditation Board.

Lord our siblings has questionable poa as well

The date on a POA is what counts. If your mother is of sound mind and signs a new POA yours would take the lead. This is not something that needs an attorney. Check with your state's Medicaid office. There is usually a state form. Sometimes either notarized or witnessed by two or more individuals that cannot be the named POA. If not in her sound mind, you need a doctor to give written note to the effect, say the home's psychiatrist.

Where were you when the POA was signed over to your sister? My guess is that you were busy while your sister handled everything in the beginning and now you are "Monday Morning Quarterbacking" the situation and want to undo everything that is already in place for you to bring her home with you instead. Is your Mother ill cared for where she is? I guess I am not understanding what your sister is doing wrong? What is wrong with supervised visits? You will always have someone to help you with your mother that way. My main advice is stop court actions. That is not what is good for your mother and ridiculously expensive. Is there an inheritance to be had? Trust me, in home care of parents is taxing and expensive and stressful. Stop pitting yourself against your sister and work with her to care for your mother and maybe you can eventually have unsupervised visits again if you stop acting this way.

Digital Banker, I hardly know how to navigate my way around this site past, like you, I thought, clicking on the questions and comments that come to my inbox, so not really sure what happened or where you're at with it, just know that with my dad, his beneficiary of my mom on his, what he called insurance, but they just called "death benefit", was not changed when she unexpectedly passed away, so then when he did, had to deal with that first before could get released, involving sending them her death certificate, which they had disappeared, had asked the funeral home to hold them when they got them till I could get back in there to get them but guess they couldn't actually keep them from dad when he went to get them, but then didn't remember and had no idea where or what happened to them, but also needed it to deal with his car, which possibly didn't really have to be dealt with, since we pretty much just scrapped it, but since it was in his will, just needed to clean it up, but was a back and forth thing between the car people and the funeral home over that death certificate till, funny, when I told the funeral home that the car people said they should have a copy in their files, she finally got up off her chair, went to the file room, and whaddaya know.....

Digital Banker, found your profile page but that's all

I can't see a reasonable reason for you not to be allowed to see your mother. Having POA doesn't mean it allows your sister to become an unreasonable dictator. Contact the guardianship board or similar institution for advice.

And we never found out what happened!!!!

digitalbanker, meallen and all, for some reason I read through this entire thread - now at least two years old when her mom was 88. ML's profile now says her mom is 90. For those of you posting within the past year, your comments lead me to believe that you did not read through the entire thread. In short, it seemed to me that ML's concerns were not due to any medical, financial or legal funny business. There are dozens of very patient, wise and loving posts to ML on this initial thread, each saying the same thing over and over and over again. Perhaps she eventually learned from them and realized that the solution was within herself. My hope for her is that she is now spending her time comforting her mother and on a path to acceptance.

I enjoy reading these and many other questions which were initiated some years ago. But it still helps others. I have just learned to look at the date of when the OP originally posts.

Time to get a lawyer. Nursing home can't do that. It wouldn't be a legal document. Not by courts standards. Good luck.