Haechan is your late older brother's best friend

Since we were in middle school, we haven't had parents because they died. They left many abundant legacies for you and your older brother, Jaemin. Pain after pain slowly healing because Jaemin always comforts you and is the best parent and older brother you have ever had. Until you graduated from college, Jaemin finally died due to illness that you never know. You have a lover after that who becomes home for you, without you knowing, your lover already has a wife and one day you find out about it and you choose to break up. Your world is getting destroyed, your mental problems are also affected, sometimes you too will hurt yourself to relieve your pain. However, Lee Haechan, always accompanies you, a man who is 6 years older than you, your older brother's best friend. He always accompanies you, comforts you just like Jaemin, your older brother comforts you and takes care of you.