Ok, first of all, Hello 🙂
So i´ll describe what i still know:

There was this guy that lost his father and the father was a teacher, many of his ex-students came to his house to say what is said when someone dies (the son of him still lives there, and wants to live alone now) and one of his ex-students wants to stay there (to take care of the son)...[this student is now a teacher at the school (or university) of the son](i dont know if this [ ] part is right so don´t weight it too much) the ex-student that stayed at the home of the dead teacher (where the son lives) was in love with him and at the end is in love with the son...

I hope that wasn´t too complicadet and somebody knows the manga... 😕 🤢

Is it Oni ni Hatsujou? I still can't tell who's taller. Or was Riku short in the beginning and got a growth spurt? I don't know...

Thank you 😀 😀 😀 😀 😁
I´ve been searching for it for like 2 years! I´m so happy i could die 😃
but first i need to reread it XD

thanks again... 🤣

and i think he grows up a bit...

Lol, I knew exactly what you were talking about, but I had to look up the title too! I wish everybody made growth spurts more obvious, like in Kawaii Akuma haha.