For those looking for past teacher/Yuri interactions in For Your Love (because lol I forgot them too): they talk together in Chapter 27 (and a small remark about the cigarettes from the teacher is made here). For hints to Yuri's situation in the meanwhile, in Chapter 34, Kwon Yuri hints at a love that he can't actually talk about as opposed to Yohan's gay love (aka his own cousin), and Chapter 48 shows us Yuri receiving a text from his cousin about the future wedding. He also get pissed off in Chapters 51-53 at both Yohan and Moogyeong because of both receiving the text and having to hear both of them talk about not being able to/wanting to confess (as in their situation, they really just can, but in Yuri's as he says in Chapter 53, he really does know the fear of ending everything with just one word.)
Man, I'm just glad my asshole son is getting his own whole story. He's a dick, but a perceptive and caring one who deserves as much of a happy ending as his friends.