In the book Tuesday's with morrie How does Mitch come to realize that morrie is ill

Luckily I read this book for a class project last year and had this same question ...

Mitch discovers that Morrie is ill when he (Mitch) is scrolling through the channels on his TV and sees Morrie on the show "Nightline" with Ted Kopel on ABC. He was telling Tedthat he's dying. And that is what happened one March night 22 years ago to Detroit sportswriter Mitch Albom. Mitch was wathing TV scrolling through channels when he saw Morrie at Brandeis University. And Morrie was telling Ted Koppel that he was dying of ALS (Lou Gehrig's disease)

He is flipping through channels and hears his professors name

Explanation:

he hears the name and goes back to the channel