He is dressed like this because he went to work at the bar and was sent home because he ripped the dress at the back. Hakdo was at his place to study but then they made out, that's why his lipstick is smudged. Hakdo went to open the door, thinking it was the pizza delivery guy which means that his brother didn't just see Sangho dressed like this, he also knows about Hakdo. When his brother asked him why he's dressed like this he answered that this is the type of person he is. His brother is rather calm but is wondering how his baby brother ended up like this (I don't think he's seriously concerned, just a little bit shocked). It's not clear whether his brother knows he's gay or not. He seems to be only wondering about the way Sangho is dressed. It was also not shown what happened between Hakdo and Sangho after the first scene of chapter 33 was cut off but they looked very happy together this chapter ;) .
Spoilers for chapter 34
He is dressed like this because he went to work at the bar and was sent home because he ripped the dress at the back. Hakdo was at his place to study but then they made out, that's why his lipstick is smudged. Hakdo went to open the door, thinking it was the pizza delivery guy which means that his brother didn't just see Sangho dressed like this, he also knows about Hakdo. When his brother asked him why he's dressed like this he answered that this is the type of person he is. His brother is rather calm but is wondering how his baby brother ended up like this (I don't think he's seriously concerned, just a little bit shocked).
It's not clear whether his brother knows he's gay or not. He seems to be only wondering about the way Sangho is dressed.
It was also not shown what happened between Hakdo and Sangho after the first scene of chapter 33 was cut off but they looked very happy together this chapter ;) .