I honestly think the focus should be more on preventing the falls and making sure she can get help safely rather than expecting her to get herself up alone. Since she already has balance issues and limited strength, trying to climb up from the floor by herself could easily lead to a more serious injury. Things like lowering the bed, adding bed rails or a bedside assist handle, using motion sensor lights, and possibly placing a bedside commode nearby can help reduce nighttime falls.
Here's a post that will help you out.
https://hopebridge.care/staying-safe-reducing-fall-prevention-risk-in-seniors/