
Okay so I think he really has illness. Like he developed it after being locked up.
Okay he was 13 y/o when his father said something is wrong with him. Then he locked him up. I think that is when where Seungho lost it and actually become ill. Imagine being locked up because they decided that your sexuality is a disease.
So maybe here is what happened
Losing sleep is actually a very dangerous thing. It causes you a lot of troubles. One common reason of losing sleep is anxiety.
He maybe developed this anxiety over the time he is being "cured". We don't know what kind of methods his father did just to cure him.
Another thing I don't know if you observed but everything that is not going according to his plan is making him lose sleep. He gets cranky.
Maybe that is why he is taking medication so he could sleep. Maybe there is just too much trauma and stuff going on he couldn't sleep. Maybe he just lost it because of this kind of situation where being gay is a disease.
All we know is that he lives in a different time. It is very different from our time. And in my opinion in this country they are more closed to the idea of being gay. So their treatment to those who's sexuality is different from them is often harsh.
Just my thoughts...

The fuck was that?
You suddenly became a saint because the FL is changing?
The fuck is wrong with these people

do you guys really want spoilers? don't say i didn't warn ya :P
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ok so i'll elaborate. it happens near the end of the novel, but a portal (?) or something is shown to penelope. in the portal thing, she sees her korean self, on the hospital bed. in the recent chapter or something, it said that she had stomach pains and problems digesting. She actually had stomach cancer. It's not stated, but it's implied that it was caused by the neglectance of her family. What I mean by that is- since her korean family treated her like shit, she thought that she didn't deserve or fit in at the dinner table. So, she couldn't eat well and it caused her to have stomach cancer.
the reason why i was so fricking pissed at the original family is because guess what- they were worried about her!! like bitch it's too late! Penelope's og self was on a hospital bed and all, and her family was staying by her side and getting a lot of doctors from around the world to save her even though they never cared before. They tell her (while she's unconscious) how they never meant what they said and bullshit.
LUCKILY! she's not those sissy fl's, and she decides to stay in the game instead of accepting the option to return back home. She decides to stay, mostly because of the ml.

I honestly didn't read the updates for almost 6 weeks to see if there will be improvement
But at this point this is just sad
Totally sad and depressing...
I feel bad for all of them
But I totally feel more melancholic when I see how Taku is... Like his mind is filled with Heasoo but Heasoo is still so caught up with something idk
So I've read a lot of threesome in some other manga and manhwa. And this is one of those that I am not really excited? I don't know how to put it on words but I kinda felt like it was wrong? Like it shouldn't be part of the story lol
Okay just ignore me I just rumbling
I agree, I didn’t really like it and I felt it was unnecessary. I kinda just skipped through it