Help in dealing with a parent

I have a 68 year old mother who has had Type 1 diabetes for over 25 years. Since she retired three years ago, she has become sedentary and prefers to stay home and watch TV. In the past year, her "episodes" of low blood sugar have increased dramatically. She is always tired and cold. She doesn't like to go out much. She has neuropathy. She is on thyroid medication which was recently increased. We find her passed out, or in a stupor and are forced to call the paramedics to bring her sugar back to a normal level. My father is finding it harder and harder to take care of her because she is not eating at set times. She prefers to stay up late at night and sleep late in the morning. We have explained over and over that she needs to eat on a regular schedule and she refuses to cooperate. She has resigned herself to the fact that one day someone will just "find her" and that will be her demise. We have asked her doctor to recognize this as depression and to treat it, but nothing has been done. What can we do?