Manolin is a dedicated student. In the end, he insists on going back to the sea with Santiago in the future to finish his education with his first and best teacher. This dedication is a great example of a tenacity to learn and of a productive respect that will lead to a positive relationship to knowledge.
For readers, the value is in learning how to not give up no matter how hard things seem to get. After all, the old man has a very simple goal, but he does not give up.
If the question relates to how the themes of the short story connect to educational ideas, I think that there are many from which to choose. I think that all stakeholders in education need further instruction in understanding that the process is as, if not more, important than the product. Santiago might not have caught the marlin, but his dreams and process by which he embraced the challenge are as important as the final product. In a setting where grades and final results are deified, the process of work construction is something that needs to be reminded to students. Additionally, the idea of remaining loyal to a goal fixed in one's mind is an essential component to a successful notion of education. This is something that is seen in the story, as Santiago faces derision from others, yet remains undeterred in his quest. Manolin demonstrates this at the end of the story when he supports Santiago, lucky or not. It is this same level of commitment that needs to be further enhanced to students in that what requires doing necessitates commitment and drive. Santiago has this and it is a lesson worth teaching to students, as well.