Bro I think that's the dad... The parents divorced, and Woojung said that he hates Sarang, so I think it's safe to assume that they don't live together. Also, his dad hates homosexuals, so he would've taken Woojung (the straight one) and the mom would've taken Sarang (the gay one).
but they also are like college or higher and those tend to not live with their parents in stories anymore.
That's true, but it's still probably not Sarang, he's probably not on good terms with Woojung. Maybe it's a friend or roommate?
I would like it to be, but it is most likely not. Then again My expectations vs reality have not won with this manga yet so no idea.
No idea who just entered. While unlikely since the twins according to the information we were shown so far hold disdain for each other I want it to be the other twin so our main can have his mind blown. Then again I also think it would be funny to have the twins compete for him despite the fact that one is against homosexuality. Again, not likely to happen. Then again I was expecting him to get punched so by the drunken twin by now so what might happen is out the window and mocking me.