although the young fishermen make fun of Santiago, he is not angry with them. What does this reveal about him? why do you suppose the old fisherman don't make fun of him?

Santiago is old and experienced, he remembers what it is like to be young, and acknowledges his own bad luck; he is a humble man. The older fisherman are well aware of Santiago's history and respect his skills. They understand what he is going through, as they too assuredly faced the same "bad luck" at points in their career.