In Tuesdays with Morrie, how does Mitch and Morrie's relationship change from before and after Morrie's illness?

Before the illness, Mitch viewd Morrie as a gifted teacher. It is not until after Morrie's illness that Mitch learned about life and mortality. In the end, Morrie teaches Mitch quite a bit about relationships and their ultimate importance in our lives. I think what he learns is culminated in this one very specific quote, actually a life lesson..............

"There is no formula to relationships. They have to be negotiated in loving ways, with room for both parties, what they want and what they need, what they can do and what their life is like." (p.177,178)