Help?

I reread this manga and i stumbled upon the history of jiwoon again. I remember i was so confused about it but i didn't pay much of an attention and after rereading it i noticed it again. It doesn't say much about his childhood except that his parents ran away and abandoned him. Why is he hated so much by the grandmother? How exactly is he and the red head related? (There was one scene where the read headed was asking about his uncle and i think maybe he and jiwoon are 1st cousins?- pls correct me if i'm wrong) From the looks of it even suha doesn't understand the situation. If anyone knows about this can please explain it to me? (⊙…⊙ )