Why was the boy crying at the end of The Old Man and the Sea?
It is clear that Manolin, referred to as "the boy" in this excellent novella, has a great emotional attachment to the old man who has cared for him and taught him the trade of fishing in a way that has given him self-respect and responsibility, in harsh comparison with his own father, who only belittles him. Therefore, at the end, Manolin in a sense is the only character who truly understands the titanic struggle that Santiago has undergone. It is specifically when Manolin sees the appearance of Santiago that he begins to cry, so overwhelmed by emotion that he does not attempt to hide his tears when he sees other fishermen:
The boy saw that the old man was breathing and then he saw the old man's hands and he started to cry. He went out very quietly to go to bring some coffee and all the way down the road he was crying.
Manolin seems to identify what this story says about the essential nature of our human condition. Santiago finally achieves his dream, but by achieving it ironically the dream itself is destroyed and Santiago is forced to accept defeat as the other fish eat his catch. Manolin's tears therefore represent both the emotional attachment and love he has for Santiago as well as an understanding of the deeper significance of what has happened.