First, Hong Haier was born. Hong Haier is the son of Niu and Princess Tiefan, but Hong Haier doesn't practice magic like his parents. Is this because Hon Hai 'er was born in the Flame Mountain and was absorbed by chance? Fire? Energy, the cultivation of three true fires, Hon Hai can control at will, which is actually quite powerful; Secondly, Nezha. In fact, there is no other fire spell in Nezha's spells except hot wheels. Therefore, the spells practiced by Nezha are totally inconsistent with those practiced by Hong Haier.
Another reason why Nezha and Hong Haier are very similar is that their images are very similar. Hong Haier is almost always dressed in red, and Nezha usually appears in red. However, this is an illusion caused by film and television dramas. After all, both of them are naughty children with strong abilities, which inevitably won't make people feel related, but in fact, no matter their age or clothes, they are just similar.
Finally, Hong Haier and Nezha, as characters in The Journey to the West, have many similarities, but we can't simply and rudely think that they are actually related just because they have many similarities. What's more, the characters in this fairy tale are not authentic. If the author didn't write them, there is no need for readers to speculate.