One possible reason could be that the twins might have some special abilities or circumstances that draw the Potters' attention more. Maybe they are more outgoing and seem to need more immediate care or guidance. Another reason could be that there is some sort of miscommunication or misunderstanding within the family. For example, the Potters might think Harry is more self - sufficient when in fact he also needs their love and attention.
Well, perhaps in this fan fiction, the Potters are preoccupied with the twins' unique problems. If the twins are ill or in some sort of trouble constantly, the Potters' focus would naturally shift towards them. It could also be that there is an external influence, like a prophecy or some sort of magical interference that makes the Potters believe the twins are more important at that moment. However, this neglect of Harry is really unfair to him as he is also a part of the family and needs their care.
In this fan fiction scenario, it could be that the twins have a stronger connection to the magical world in a way that the Potters are not fully aware of. They might be unknowingly involved in some magical events or phenomena that require the Potters' full attention. On the other hand, Harry might seem more ordinary at first glance in comparison. But this is a wrong perception as Harry has his own potential and needs love and care from his parents. The Potters should have been more balanced in their attention to all their children.
It could also be that the Potters are under some sort of magical influence or curse. In the fan fiction world, there could be a dark force at play that makes them see the twins as more important. This force might be manipulating their emotions and perception, leading to the neglect of Harry.
He might become withdrawn. Feeling unloved and ignored, Harry could start to keep to himself more, not sharing his thoughts and feelings with his family. He may also become resentful towards the twins, seeing them as the cause of his being neglected, even if it's not entirely their fault.
Harry might become withdrawn and introverted. Feeling unloved and unwanted, he could start to keep to himself more, spending time alone in his room or exploring the grounds of their home alone, trying to make sense of why his parents seem to favor the twins.
Perhaps there's a plot against Harry by some dark forces, and the Potters believe that only they can protect him properly. They might think that the people who have been taking care of Harry so far are not equipped to handle the new and more dangerous threats. Also, it could be that the afterlife in the wizarding world has some rules or opportunities that allow them to try and get Harry back into their family fold. They could have been given a second chance, so to speak, and are eager to take it.
One possible motive could be that the Potters discovered some dark plot by the Malfoys involving Harry. Maybe they found out that the Malfoys were planning to indoctrinate Harry into their pure - blood supremacist ideology against his will. So, to protect Harry from that, they kidnapped him.
I'm not sure specifically if there is a 'Potter's Neglect Harry' gay fan fiction. Fan fiction is a vast and diverse realm, and while there are many types of Harry Potter fan fictions, this particular one may or may not exist. It could depend on the creativity and interests of individual fan fiction writers.
Sirius Black could also be part of it. He was Harry's godfather. He might have escaped from Azkaban earlier in this fanfic. He teams up with the Potters to rescue Harry. He could be the one who scouts out the Dursleys' house before the actual rescue operation, using his skills as an Animagus to stay hidden.
One reason for Blacks to read Harry Potter fanfiction could be the representation (or lack thereof) in the original series. Fanfiction can sometimes address issues like better representation of diverse characters. For Potters, it could be the curiosity of seeing their name in different fictional scenarios within the Harry Potter world. Also, the popularity of the series means there is a vast amount of fanfiction available, and both Blacks and Potters could be attracted to the variety of stories, whether it's about new magical creatures, different relationships between characters, or alternative endings to the main story.
One possible plot twist could be that Snape discovers some hidden magic in Harry that he didn't expect. Maybe a power that's related to the Potters but also has a connection to Snape's own family. Another twist could be that the other Potter family members don't approve of Snape adopting Harry, leading to a family feud within the wizarding world. And perhaps, there could be a dark force that tries to use Snape's new relationship with Harry against them.
Another possibility is that Harry could find a hidden diary of his parents. The diary could contain their thoughts, experiences at Hogwarts, and even some secrets about the wizarding world that they were involved in. It would give Harry a more personal connection to his parents and their lives before him.