Does the nursing home have the right to request financial evidence that we have the finances to pay private pay?

Also the supposed "20 days" of insurance coverage left may NOT happen. The facility needs to know how to bill & bill ASAP if that happens.
If their at a facility & in rehab phase with Medicare as their primary insurer, medicare will pay ONLY IF they are meeting certain standards of progress. Other insurers take this same approach. It's really important to speak with their PT, OT, ST regularly to see what's what so you can plan for the near future with as little financial glitches.

We were asked to provide financials to the discharge folks at the hospital where my mom's hip repair, post stroke, was done. It was clear to all that in all likelihood she wasn't going to return to her AL. They were able to guide us to a home that would accept Medicaid after three years of private pay was up.

cwillie, they have a pretty good idea which patient will NOT progress in rehab. For my MIL, they knew, the left side was gone, she could not go back to assisted living. They were right. So we worked with them and they worked with us.
I do know of a woman who did NOT work with the facility, she flat out refused to even discuss Medicaid because "they will keep the whole check and I have bills to pay." She needed the nursing home and she was mentally competent so she had the right to refuse to cooperate. They gave her a 30 day notice. She still refused. She is now in a homeless shelter.

They are preparing to apply for Medicaid, unless you signed the admission papers as the responsible party. Better check on that. Read all the papers you signed. Assuming you did NOT sign as a responsible party and were smart enough to write POA after your name, you still need to provide 5 years of financial information for the Medicaid application. Yes you can refuse to do this. That means they can refuse to keep her.

I'm just asking to be ornery and out of genuine curiosity as well, if the person is staying in rehab only until the insurance runs out what business of theirs is it whether they are a millionaire or a pauper?

We had to provide financials BEFORE mom was admitted to rehab. This is standard.

SonTheCaregiver, think of it this way, your Mom is "renting" a room, thus the "landlord" needs to know if she can afford it.

Could be the nursing home wants to see if Medicaid might be in the future, and if yes, then to start the applying process now. Or it could be that the nursing home doesn't accept Medicaid residents.