
It’s actually not a spoiler since this topic has been discovered in the webtoon (it’s just not posted here, the continuation of chapters after 87” but neo is not Noah’s biological son. Abel is. Noahs wife, parish, had an affair with Noah’s brother when they were teen. But they pinned the father as Noah, even Noah believed he was the father. Until later on he found out Neo is the result of his wife and brothers affair, and not his own son. Abel, tho, is his own son. It’s his and parish’s (Noah’s wife) son. It was shown before that when Noah found out Neo isn’t his son, he started neglecting Neo and showing more affection towards Abel. Parish followed in his steps and was a complete butch towards my little baby Neo. But after the whole acopolypse shit, in the very first chapter, it is shown that there’s some sorta thing happening between Neo and Noah, causing Noah to realize his mistake. He wanted to save Neo in that scene. But he died before he could, and that’s when this “Law” guy appeared. He brought Noah back in time for him to fix his mistakes, change the future. Which goes to show why Noah is more worried and focused on Neo. He realized and admitted he treated Neo badly and didn’t wanna make the same mistake. He wanted to make up for his mistakes. But by doing this, he started neglecting Abel... bc in the future where he came from, his own family he cherished so much (Abel and Parish) betrays him. I think those 2 betray him but Neo doesn’t? I didn’t understand that part much but- because of what Abel and parish did far into the future, he’s really... hostile towards Abel. Like avoiding him, as you can see from the story. Basically, he’s making the same mistake he did with Neo, with Abel now.
Sorry for making this long, I noticed few questions like “who’s his actual child” or “whys he showing so much attention to Neo” And all- sorry if this is even pointless- like if you caught up with webtoon you probably know all these haha..

Yeah. I believe it’s because he abandoned Neo since he was little and always neglected him. UNLESS there’s another factor that could be counted as Noah betraying Neo. If there is any it hasn’t been revealed yet.. there’s a lot of stuff that has yet to be revealed about Neo and Noah’s future relation.
.....
Is neo his real son and abel not? Did they fudge the paternity test?