This really depends so much on what you have been asked about the story or what you yourself want to say about it. It's pretty hard to tell you a thesis statement without knowing either of those things.
If I were told to just write something about the story, here are some things I might use as thesis statements:
- In this story, the actions of Bob and his friend Jimmy Wells show us that two people from similar environments can turn out to be very different people.
- In this story, Jimmy Wells' behavior demonstrates that good people will always put morality before friendship.
- This story was overly predictable in that any reader who got halfway through the story could be pretty sure of how it was going to end.
Any of those would work for me if I were writing a short essay on this story.