What small lie does the old man tell the boy Why doesn't the boy confront Santiago and make him admit he is in dire straits?

The old man, Santiago, tells the boy that he has caught fish and is fine despite his struggles. The boy, deeply caring and respectful of Santiago, chooses not to confront him about his dire circumstances, as he understands the old man's pride and desire to maintain a semblance of dignity in the face of adversity. This dynamic reflects the bond they share, where the boy wants to protect Santiago's feelings and uphold hope, even in tough times.