Mom's been in nursing home for over a year and a half, brother has POA, but has only been there 4 times, I've been going several times a week, bought her furniture, clothes, snacks, drinks, paid for her heir to be done, taken her to church, until she not able to go. She's in last stage of dementia, the end is near, brother has been called to make decisions, we don't agree on things he's done financially, so we've not spoke in over 2 yrs. When he saw me with mom, he had administers ask me to leave the room so he could visit, I did, about 15 mins later administrator came outside to tell me my brother was POA and didn't want me there and I was not allowed back on property without something from the courts saying I can be there. I ask for what reason, was told he didn't give one, but he was POA so what he said went. I told administrator I have been visiting mom since she was admitted and brother had only been there 4 times, he said yes, he's seen me there a lot and had never met my brother til that day, but he was POA so what he said went. Can they really keep me away from my mom for no reason except a power trip?
In some cases, like the toxic child, POA limiting visitation is a good thing.
In some cases, like the POA getting even with other siblings, limiting visitation is a terrible thing.
Depending upon the wording of the POA, the POA should be acting on the best interest of the grantor. Unless he has a reason why you must be kept away, then he's not acting in your mother's best interest by keeping her daughter away from her, especially as her end approaches. Good luck.
Since all the staff knows you and in my experience admins rarely leave their offices I imagine that once brother is out of the building nobody will stop you if you continue to visit as usual.