Can we legally sign for her?

We literally had a rehab try to force us to sign (Dh and Sil had joint POA) when FIL went to rehab the last time. I made a total nuisance of myself because they kept pushing for it and I said absolutely not because he was competent to sign his own paperwork and neither of them was signing anything whatsoever. They kept pushing saying it was just a "placeholder " I said well if you just need a placeholder then you can place his name there because no one but him is signing that paperwork. I still don't know why they were so pushy about it except that he was in the bathroom and had been for sometime and they were antsy to get the paperwork done because it was late on a Friday afternoon.
The point being, if your loved one is competent, there is no reason anyone but them should have to sign the paperwork, POA or not unless they are incapacitated, and UTI I don't think counts. And if you don't have POA I don't think you can legally sign anything anyway.
BUT under no circumstances sign anything accepting responsibility to pay for anything yourself.
This particular place, even though they didn't get my husband's signature on anything, did get his contact information....and had the literal nerve to send us a freaking bill for services...
You can bet that I blew up the billing department when that one arrived...they fixed it fast LOL.

You aren't allowed to sign for a competent person. Only, if you are the appointed guardian of an incompetent person.

Her UTI will clear up. She can sign the papers then.

Even an X can be a legal signature for someone who has visual or physical deficits that make signing difficult. If she is cognitively unable to sign (either temporarily or permanently) the NH could have a hard time enforcing any contract she signs, but if they accept her mark that is their problem, not yours.

If you have no POA, you have no authority to sign on her behalf.

You don't want to sign yourselves as "responsible party" because that makes you liable for the bills.

So, the choice is she signs (we put NH paperwork in front of mom post stroke; I doubt she knew what she was signing)--POA brother was not there at the time-- or the paperwork goes unsigned.

Hope the lawyer has good advice.

We did the first time MIL went into AL. When that didn’t work out and she went back home, the next and final move we had POA so signed on her behalf.

Aunt should sign her own paperwork.

Do Not Sign anything that says you will guarantee payment. It definitely would be best to have the attorney go over the admission paperwork and advise, but if that can't be done make sure you don't sign your name next to any line that states you will be financially responsible. Be careful when you read, and if any line seems confusing, make sure you get clarification.