Hello, she is very old n getting irritated or angry at this age is natural too. They do feel quite lonely especially if bed ridden.
Next Steps
If you people do have kids at home, make them spend time with her. Her kids need to sit beside her n talk to her of past memories n happier times that involved her.
Health Tips
Please try to take time out of your busy schedules n do see the difference in how she responds to this. Take care of her n make her feel wanted.