Any tips for elderly with severe RA and unable to use arms? OT didn't help.

On a previous post you say ur caring for elderly parents with no help from ur brother, the golden child.

As said, the OT could have given you tips. OT is usually to help learn how to continue to do ADLs. Maybe Mom could do with physical therapy.

Your posts talk about how Mom can be so mean. Maybe its because of the pain she is in.

There is no information in your profile to give a clue as to other issues going on.
The same adaptive tools that someone that has been paralyzed or has had a stroke might help. I would ask the PT/OT therapists if they have any suggestions for tools and devices that might help.
this person would be full care and either would be cared for at home or in a Skilled Nursing facility.

What is their current situation? Are they living alone? Who is caring for them?