Does Mom have to have rehab?

If medicare is paying, yes she has to do it, or they will stop paying at some point and send her home, maybe mom knows that. If you can't do it any longer tell the Social Worker at the facility she is in, be firm, just tell her you are unable to provide the necessary care any longer. You are fortunate she is now in a facility because they are responsible for discharging to an appropriate situation. That is not you, but you need to make sure they understand that.

Give her time, maybe once she realizes at the nursing home that when she yells for the employees and they don't come right away, maybe, just maybe she might get out of bed.

If she already has Medicaid, she is all set. Let her yell at them instead of you, you have earned a break.

People with RA, especially need the PT. (My sister was completely disabled from it and died at age 69.) It becomes worse, quickly from just laying in bed.

Good luck. You can't make her happy at home.

Pain and inflammation makes you tired. Tired and depressed. Maybe her RA care could stand to be optimized; it is a bad disease, worse than a lot of people appreciate...hopefully she is on something besides just NSAIDs for it. Maybe she could be treated for depression. Laying in bed does mean she will become debilitated to the point of really being unable to do anything else.