In my opinion, first reason for he become unstable was dojun because of u don't love someone my u marrying him just coz of pressure and u already in a suitable ages for married? The one other party will become the victim.
The follow mybe his manager will send him to hospital and call kyungsoo or mybe it better if kyungsoo not knowing his situation. But whatever the auther is really the great
I really like the flashback here but after I read the novel this is the most part I want to skip