Chapter 2 is kind if difficult to explain. I think that he and his ex used to live that apartment and when they broke up he moved out but still had lingering feelings for her and thats why he shows up as a hologram or something. But I think after meeting the guy he started fading because his lingering feelings began to disappear for the ex so he had no ties to the apartment anymore.
The end of the chapter is an open ending since they don't get together officially, they are more like friends and we can imagine how many bl's there are of a friend liking a friend one widely.
Sorry this got too long
Thanks for explaining I was so damn confused
Thank youuuuu! (づ￣ ³￣)づ
Someone can explain me, what happen in ch2, I can't understand. ಠ_ಠ