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The brothers kissed. But I think Seo-In's brother is the one w the problem.
When the Dr. Stopped by to hand SI some food she said : "I may be your brother's doctor but I've known you forever." Upon a reread I deduced she may be a mental health specialist and not a family doctor....since she said that she is the brother's doctor (Seo-In's brother)
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No they're brothers. He might be hospitalized for mental health treatment. Loss doesn't necessarily mean death. Loss could be mental thing: such as finding out your son/s are incestuous. And it's not his sister, but his mom, that he was talking about. When the Dr. said "Unnie" it is she who is referring to Seo-In's mom because Seo-In's mom is probably older that she is. She did not say "your Unnie" which then would indicate that it is her sister. - read my comment to the post above
Also, the ones that kissed were the brothers. They had the same mole.
Is it incest??? Pls tell me its not