dear pt noona,
For backpain I suggest you give her massage. The old classic swedisch massage to relax and improve circulation should work fine.
She will need to understand that she should not stay in one position for too long.
Tell her to move whenever she feels like moving, in whatever direction she feels is OK (and possible) = ideomotion.
Teach her to ask others to move her if she cannot do so herself herself.
Even passive movement can often help people in pain from being in the same positions for long (bedridden)
good luck.
Do you know about the www.ifglobal.org website?
Is great and with a lot of information in many languages.
good luck
Esther