Trying to find this pls help!

So basically I'm trying to find this manga so pls help if you do know it

So basically the mc was like a tsundere with brown hair and eyes (I think) and I remember that he made a post on the internet about finding a certain guy before he leaves this world or to somewhere else and he wants to find him because in the past he said he would bring the guy breakfast right by his window but he never did and then proceeds with flashbacks about highschool where he met the certain guy sorry this is a faint description