Sis is recovering very slowly

I don't know how it is for most people- if there is an average reaction at all. My sister was diagnosed with esophageal cancer last spring and was given a very good prognosis. She underwent chemo and radiation, and had a very tough time of it, but she came through it and recently got a clean bill of health from her doctor. The thing is, it's been two months since her treatment ended. She is very depressed, and VERY VERY tired. She sleeps most of the time. In addition, she is very, extremely mentally confused- is constantly losing things- is having trouble paying her bills, can't remember who she had a conversation with about what. She is unstable on her feet and can't go out without assistance. I live across country from her so there is little I can do. She is still on pain medication. They are weaning her off very slowly, but I'm not sure if the pain medications account for all of her symptoms. I know there is a thing they call "chemo brain", but what she's going through seems very extreme. Her chemo ended about two months ago, before the radiation. Does anyone have any recovery stories or input as to whether this would be considered normal recovery?