I'm sorry to hear of your Grandmother's fall and confinement to the wheelchair. Evidently they cannot repair the hip to restore her walking? I also assume her doctors are aware of her aggitation and have considered medications to help, just as people take for anxiety due to other situations? My grandmother was a realtively good patient then in her mid 90's became belligerant and a medication was added to her morning coffee; she was not doped, but was calmer and not aggitated and could enjoy the little things she enjoyed (a banana being at the top of her list!!).
She needs things to do to: 1. keep busy, occupied, happy, fulfilled and 2. to assist her feeling of independence and to make her feel necessary and that she matters.
Does she sew? Can you bring her real (or created) clothing repairs such as buttons to sew on? (if you don't have any, get something from a thrift store and remove a button or two...). Does she read? Can she still read or would she enjoy a book on tape or CD? Could she sort and date and identify photographs and even put them in albums? Coud you give her a tape recorder and ask her to record her life with all the details? Are there stimulating activities where she is? Music, TV, just a common room where she can see others and watch the help come and go as they do their duties? Can you help the facility bring in entertainers--volunteer groups to sing the old favorite songs of years gone by (or start a group yourself; the whole family could get involved: use recorded music, print up the words, and have fun!).
As my grandmother regressed I gave her children's picture books to enjoy, her favorite being one of Chirstmastime with pictures set in the late 1800's/early 1900's (she was born in 1894). She really enjoyed those.
I hope this helps you and I'm sure you'll think of many other ideas that would suit her as you imagine being in her position at this time of her life. You are lucky to still have her and she is lucky to have you as you are very caring and concerned for her well-being and quality of life.
Post back and let us know how she and you all are doing, okay? We'll be thinking of you!