Seo Jun is protective about Ju Kyeong getting close to Suho because to him, Suho is definitely not an ideal friend and as such, pretends to be close to Ju Kyeong to deter her instead.
He says that he hates her illness, not her, and he hates the fact that his father uses her to get investments.
Do-hwa reads that Dan-oh needs surgery and starts to burst into tears again I luff him , and she threatens to kill them both if they mention the surgery to Haru.