What is your understanding of hospice?

I know what hospice is. What I am getting confused about is the qualifiers. A little over three years ago my father was place on palliative care by his drs. At the time it was explained to me as the step before hospice - that more care and comfor needed to be provided but end of life was not in the immediate future. After a month or so it was determined that hospice would be more appropriate as they were sure he would die within six months. They told us that a six month time line was the line between the two types of care. That and a diagnosis of cancer, congestive heart failure and lung disease(s). Here I keep reading "get hospice involved". One poster even stated that end of life is not a required qualifier. I am confused now - I also thought hospice was a federal mandate that did not vary by state. My mom has lost her mind but physically she is probably in better shape than I. God knows her blood pressure is better, lol! Can anyone advise? I don't want to pursue another dead end.