OKAY Okay So I feel like, see the two siblings look very alike right? And it seems that Ike is attracted to Jooyoung, the sister. Therefore, I'm guessing he told Jooheon to say I love you with the blinds on because it would feel as though Jooyoung was saying it. I think he could possibly be in love with Jooyoung. Also, I don't think Jooyoung would tell him to do all of this, I feel like that text was a red herring.