Shortly before he died last July, the former N.F.L. quarterback Ken Stabler was rushed away by doctors, desperate to save him, in a Mississippi hospital. His longtime partner followed the scrum to the elevator, holding his hand. She told him that she loved him. Stabler said that he loved her, too. "I turned my head to wipe the tears away," his partner, Kim Bush, said recently. "And when I looked back, he looked me dead in the eye and said, 'I'm tired.' " They were the last words anyone in Stabler’s family heard him speak. "I knew that was it,"...