He might get really immersed in the fanfiction world and lose track of time on his way to Sirius. Maybe he'll start imagining the characters from the fanfiction in Sirius' place.
Sirius may also be angry at first. Given his protective nature towards Harry, if he misinterprets the situation as Draco causing trouble for Harry, he would likely step in assertively. But if it's a situation where Harry and Draco have a more positive or friendly interaction in the fanfiction, Sirius would have to re - evaluate his initial reaction.
There could be unforeseen magical consequences. Time - traveling is a tricky business in the wizarding world. By changing Sirius' fate, Harry might accidentally create new problems. For example, the balance of magic in certain areas could be disrupted. There might also be changes to the Hogwarts' community. Students and teachers who were affected by Sirius' situation in the original timeline might act differently.
There's a chance he'll run into Ron. Maybe Ron is looking for some new wizarding sweets at Honeydukes, and they end up sharing some of the treats while they continue their shopping spree. And it's possible that they'll see Neville there too, who is searching for some rare plant seeds for his Herbology studies.
One reason could be Harry's impulsiveness. Harry often jumps into dangerous situations without thinking, and Sirius, being his godfather and having a protective nature, would shout at him to make him realize the risks. For instance, if Harry decides to go after a Death Eater alone.
He could be quite entertained. Since fanfiction often explores uncharted territories in the story world. Maybe he discovers new relationships between characters that he hadn't thought of before, or new adventures that could have happened in his universe. This could inspire him to think about his own experiences and relationships in a different light.
In such a fanfiction scenario, Harry could use a Time - Turner. He'd have to be extremely careful not to disrupt the timeline too much. First, he'd need to figure out the exact moment in time when he could prevent Sirius from getting into the dangerous situation. Maybe he'd have to go back to before Sirius was framed for the murders. Then he could expose the real culprits and keep Sirius out of Azkaban.
It could enhance their relationship if the fanfiction gives Harry new topics to talk about. For example, if the fanfiction is about a magical adventure similar to their own experiences, they can bond over it.
The 'Harry Potter' books are set in a magical world full of its own stories, prophecies, and secrets. Sirius is a complex character with a lot on his plate. He has to deal with his family history, his time in Azkaban, and his loyalty to his friends. Fanfiction is a form of creative writing by fans outside the original story. Sirius doesn't have the time or the inclination within the context of the story to be reading fanfiction. His life is too filled with real magical drama and danger.
The best part about reading Harry Potter book 7 fanfiction is the creativity it offers. You might find stories that combine elements from other fantasy universes, creating a really unique reading. It also allows for more exploration of the magical world's lore. Maybe there are fanfictions that explain in detail how certain spells work or the history of some magical creatures that were only briefly mentioned in the original. Additionally, reading fanfiction can make you feel part of a community. You can discuss with other fans about the different plot twists and character developments in the fan - made stories.
He might meet some strange magical creatures there that are used for experimental treatments.