Wow

I don’t remember if we ever learned what got him fired from his job and unable to work in other hospitals but I remember he was pretty traumatized by the whole situation so maybe that has to do with why he’s like this now? Plus imo Dan was a lost cause as soon as Jae was nice to his grandma lol he’s a grandmas boy through and through

If I remember correctly a doctor who worked with him sexually assaulted Dan and when they were caught he got the blamed or something like that

Well first, he grew up with his grandma who loves him wholeheartedly, yes, but it’s still not the same with growing up with actual loving parents. Then granny became sick and so he ended up in a huge debt and even more debts after borrowing money from loan sharks. We can assume that the loan sharks gradually started threatening him when he can’t pay the amount they want so the threats became physical assaults up until they tried to sexually assault him. Between the loan shark problem there’s the rapist doctor who tried to assault him too and he ended up getting fired. He’s doing multiple jobs because he needs money so he was extremely exhausted both mentally and physically. That's plenty of trauma. And as bad as this might sound, he is actually in a better situation with Jaekyung. If Jaekyung didn’t save him he’ll probably end up getting trafficked in brothels and once the traffickers find him unusable, he’ll end up dead with his organs harvested and sold.