
I think they're blood. Probably full on brothers.
I reread the ch. where the Dr. came by to drop off the food for SI and she told him, "You should contact your mother" and asked him what he is doing there instead of his home, wherever "there" is. So it seems like the brother may be the one his mom is worried about. Seo-In's thoughts: "It's not that she (his mom) worries about me, but more about what she has lost".
And the Dr., upon my second read, I realized, that maybe she isn't the family Dr. But a licensed therapist or psychiatrist, since she said: "I may be your brother's doctor but I've known you forever" which indicates it's his brother who has the problem. But the scene YeongWoon saw: was it set up by the brother to make YW jealous/stay away from his brother? Or was Seo-In also in (participates) on the incest thing? It would SEEM it's the brother who has issues since it's the BROTHER'S doctor. But Seo-In seems to have his own dark side too. Idunno.
But I'm a bit disappointed in Manager avoiding Actor. It seems like the Actor likes the Manager. I don't like when there're 2 people interested in 1 person, but the plot is only favoring one sidedly to the 1 out of 2.
And, what's with that brothers were kissing each other in class?
ლ(´ڡ`ლ)
And, Manager was in love with that blonde since then.
╮( ̄▽ ̄)╭