One possible reason could be that his newfound 'godlike' powers make his family feel estranged. They might not understand his sudden transformation and the magnitude of his power, which creates a sense of fear or discomfort, leading them to ignore him.
He could also distance himself from them. Naruto might choose to avoid his family, not wanting to be around them as a way to show his anger. He could move out or stop participating in family activities.
Maybe he has some personal grudges or misunderstandings within the family in the fanfiction. It could be that something happened in the past that made him feel betrayed or unappreciated, so he refuses to offer help.
In fanfiction where Naruto is hated by his family, it could be a very dark and angsty take. Maybe the author wants to explore the idea of Naruto facing even more hardships on top of being an outcast in the village. It could lead to a very different Naruto, one who is perhaps more bitter or desperate for acceptance outside of his family unit.
One possible reason could be a long - held misunderstanding. Maybe Naruto discovers some family secrets that he misinterprets as betrayal or neglect. For example, if he finds out that his family had made some sort of pact that he disagrees with, it could lead to his rejection.
One possible reason could be that he has some unresolved issues from his past, like the absence of his parents during his childhood which made him feel a sense of detachment. Maybe he is so focused on achieving his ninja goals that he unconsciously starts to ignore his family. Another reason might be some sort of miscommunication within the family. For example, if there are secrets that the family has been keeping from him, he might feel betrayed and thus choose to ignore them.
Well, in fanfictions, often the plot takes a different turn. Naruto might hide from his family because there could be some sort of misunderstanding. For example, there could be false rumors about him being involved in something bad. And he might think that his family would believe those rumors without giving him a chance to explain. So, to avoid the immediate confrontation and judgment, he chooses to hide.
He might try to prove himself. Naruto has always been a determined character. So he would likely strive to show his family that they are wrong about him. He could do this by achieving great things in the ninja world, like mastering new jutsus or completing difficult missions.
One reason could be that Naruto has been through a lot of hardships related to his family in the fanfic. Maybe they didn't support his growth to this godlike state, or they tried to use his power for their own gain. For example, if his family had always been jealous of his potential and when he finally reached this ultimate power, he realized their true nature and decided to cut ties.
Another reason might be that Naruto has been influenced by external forces. Maybe he has made some bad friends or been involved in some situations that made him think being cold to his family was the right thing. He could have been brainwashed into believing that his family was holding him back from achieving something greater.