I think if you consider how Roger at the end of the story is different from Roger at the beginning of the story, it is very obvious that Roger is not a static character, but a dynamic one. Let us remember that static characters stay the same throughout the text: they do not mature, develop or change significantly. Dynamic characters, on the other hand, are characters that do not remain static but evolve and mature, growing in their self-knowledge and maturity.
When we think of what happens to Roger, it is clear that the impact of Mrs. Jones is massive. We leave the story knowing that he will have a very different kind of life after meeting her that day than if he had never have met her. The understanding, compassion and generosity that Mrs. Jones shows him, and the advice that she gives him, clearly shows the way that his character has changed. Note how even before the end of the story he has gone from being a thief to asking Mrs. Jones if he can go and buy her something.