Mitch is writing to us now. He looks back at the person that he was before he re-met Morrie. His regret is that he didn't go back and see Morrie sooner.
The most important thing that Morrie taught Mitch is that it's never too late to do anything—Morrie was a living example of this.
Mitch is able to get hold of his brother in Spain shortly after Morrie dies and he opens up enough to tell him that he loves him.
Mitch also admits that Morrie was in cahoots with him about writing this book. They looked at it as a "last thesis" (27.9).
Mitch concludes by turning teacher himself, so to speak, and addressing us. He tells us how valuable a lesson it is to have somebody like Morrie in your life, who sees your worth and helps you uncover it.