I think it might be the fact that they're alone now. Back then, they were living with the mom and Haebom probably couldn't legally live on his own. Now that he can though and they're in college, he's raising some eyebrows.
Ooooooh that makes sense even though he completely forgot him haha
Nah i think taesung's dad and mom werent on good terms with each other...they might've divorced or something like that...so he didnt know what was going on in the family...and he didnt know about Haebom either i guess?
Woah I didn't even think of that, I just assumed he was always absent and focuses instead on his work. But what you're saying explains why taesung's mom works so much too
Haven't they been living together since like day 1 back in high school? Like how did the dad not know that someone else was living in his family's house. I get that dad isn't very present in their family but he should still know about a whole entire other person living with his wife and son