Mom taking care of her unworking mother. Any advice?

As I mentioned before, I am writting on behalf of my mother who is the caregiver of my 72 year old grandmother. My grandmother has lived in the US for over 10 years and has never worked. She had her green card and recently she passed her citizenship test!!! She doesnt know how to read or write ,she is probably at a first grade level. We bought her a tape recorder and that is the way she learned..
Well, my grandma has many health issues. She has only one kidney, arthiritis, hip replacement, blind from one eye due to stroke.. and many other problems that I fail to take note. She grew up in Ecuador and most of our expenses for health care have been traveling to Ecuador to get her examine, because we don't know how to get her healthcare here. My mother works full-time and makes enough money to qualified for medicare.. so apparently my grandma doesn't qualify for medicare nor medicaid. My grandma provides for my grandma 100%. What resources are out there for my mother to take care of grandma, and what healthcare benefits can we get for grandma... Please guide us to ease the aging process..