He had something in his head. Not telling him the truth because he was afraid he became his useless adopted son? Is plainly stupid. Taeksoo grew up in hardship, he saw his parents do it, so he is doing it. Then he gave us that crap? Not telling him that they are blood related? Stupid ojiisan
I don't know if I should appreciate it or be weirded out. But for now I decide to appreciate what's been given to me.