Can Santiago be found in the real life? Or does Santiago remain a character only in a novella?l need a literary answer.
Santiago is an archetypal character, which means he is and will be symbolic of others before (Christ), during (the great DiMaggio), and after him (the father in The Road). He is not only born to suffer, but to learn from and teach his suffering to others. In this way, he is like Christ and Manolin is his disciple. He is like the great (but injured) DiMaggio toward the end of his career, and the readers are like his sympathetic fans.
The novella is not an allegory: Santiago does not stand for only one man suffering, so "no," he does not remain only a character in a novella. He transcends time, culture, and age, so that any reader, young or old, can identity with his suffering and respect his wisdom.
If you've read Cormac McCarthy's The Road, you will see Santiago in the father: a dying man who goes on a dangerous quest to keep his son alive for the future of mankind. The marlin is Santiago's quest and emblem of suffering (as it is eaten by sharks). The father's quest is to follow the road to the ocean to find warmer climes, but the beach is no warmer than inland, and he dies. But, in the end, the finds a family, thus fulfilling the father's quest and redeeming his death.