Evan’s father and mother, Chuck and Mary, invited me recently to talk at their kitchen table in a handsome brick home on a cul-de-sac north of Indianapolis, surrounded by photos of their three sons, strapping young men with big smiles. Evan, 6-foot-1 and 200 pounds, began to struggle with depression when he was 19, they said, by which time he was in his 11th straight year of playing tackle football with that relentless abandon of his.

“He was fearless and not afraid of pain,” Mary said. “Stick your nose in there. He loved the game.”

As afternoon yielded to twilight, the couple spoke of their son in tenses that alternated between present and past. They have decided to speak publicly about his brain injuries and his struggles with depression. With their words, they hope to lead other parents to an understanding of C.T.E., and to a more cautious relationship with tackle football.

The Hansens are observant Catholics and believe in providing succor. Evan volunteered at his church, working as a Spanish translator at a food pantry for homeless and poor families. At Joe’s Butcher Shop, he would greet regulars with a buoyant hello and a touch on the arm. At school he ran in no jock clique. More than once, parents asked him to speak with their children and help work through one adolescent struggle or another.

Then depression’s whirlpool began to tug at him.

Mom, Evan said, my life is so good and yet I feel dark.