As one of the themes in OMS, there is the theme, "There is Honor in Struggle, Defeat & Death". Santiago was struggling against defeat.
He could not catch fish for eighty-four days, but he never gave up though he is old.
Also, he was struggling with Marlin for three days.
I think he is a strong person.
I also thought that the nature is severe world.
Everything is not always going well.
Marlin remained only skeleton, Santiago and Marlin were the token of honor, brave of fighting with the shark.
I thought Santiago had a gender opinion, "Man is not made for defeat", however I felt his thought was powerful and fantastic!