If mom has lived with my sibling for a year and suddenly unable to make any desision. Does he have the right to put her in a home?

My brother moved my mom to his house a year ago left everything she had behind. She was going to just go stay a couple of nite. Bue he never brought her back. Left all her stuff behind .in the 2 months my mom has gotten real sick she's 92 and had the being stage of alzhmeirs she got a uti had it for 2 wk before they took her to hospital she seemed a bit confussed but not total lost . The hospital said it was due to the uti 2 wks ago I get a call my moms back in hospital. I rush there which is a 45 min. Drive for me. When I get there I could not belive my eyes she had lost maybe 30 lbs couldn't talk walk eat r even go to bathrm. Next thing you know I am told there putting her in a home 5 blocks from them my siser in law works there. My mom has always lived in the town I do, this is where her hubsnd is buried here so is her sister.most of are family lives here. Her burial site is also here. There no poa. Mom is incomptent and going down fast dose he have the right to put her there are can I move her to a home here