My mother is 90, on oxygen and has multiple daily breathing treatments, cannot lie down to sleep without her CPAP on and has been taken to the ER several times at her request because she is unable to breathe . She no longer has the strength to walk on her own since she is dependent on her electric wheel chair. Is she in end stage congestive heart failure?
My Mom [also in her 90's] had bladder cancer and her doctor said the cancer wouldn't cause her passing. Same was said about her blood pre-cancer. What caused my Mom to pass was a serious fall with head trauma, something we never expected.
Other than that, she could live another 5+ years IMHO. Have you tried to get her up to walk? HomeHealth has Physical Therapists that will come work with her and you. I used them with my dad before he passed and now I use them with my DH (95 and counting)
Ray's sister lived to almost 95 and had been wheelchair and bed-bound for at least 5 years prior to her passing. Not moving on your own doesn't mean the end is near.