they said that yuki has a mental problems and very obsessed of mafuyos first. he wants everything even the strands of his hair, And mafuyo has problems expressing his feelings since he was abuse and lock up by his own dad. And mafuyo really dont want to take the guitar cause he will be reminded by yuki but yukis mother beg for him to have it. Its sad cause mafuyo blamed himself for yukis death when he clearly didn't do anything yeah he said would die for me then?. but he abused he still hasn't recover yeat cause a trauma is not something to taken to lightly. And when mafuyos singing theres a panel that he regret saying that to yuki, but we cant do anything about it since every decision theres always regrets.
Yuki was paying too much attention to Music and so Mafuyu felt neglected and the two had an argument where Mafuyu yelled out "Then?! Can you give your life for me?!"
And then one day during the winter holidays, Yuki was drunk and suicided because he thought it might be fun.
This is what I understood about Yuki's death
Guys pls dont fight. Yuki was too inlove with mafuyo that he would do anything for him as for mafuyo he is inlove with yuki but he ates when he feels being abandoned cause his father did that mafuyo. And yes yuki is depressed we cant actually see it since yuki is a happy go lucky guy but depression is there he is indeed depressed. yukis mom beg for forgiveness to mfuyo cause he will leave him too. Mafuyo was emotionless but ue helped him alot. cause yuki isnt just a lover he is his bestfriend the one who helped him when his father sent to prison.
No matter how little Yuki's appearance in the manga was compared to others, just reading his name ( or seeing his back) makes me feel sad, sentimental and this feeling of grief that is hard to forget. BUT no matter how I try to understand the story, I still couldn't get a proper conclusion as to why Yuki committed suicide. Can somebody enlighten me pls.