Wait so the true couple is the author and his lover?!?
From what I understand, the story is a biographical excerpt from the life of the mangaka's gay son, Akira. I could be wrong and it could be a ghostwritten autobiography (some editing would be necessary because of the limitations of the manga format.) Akira is portrayed in the story as the narrator, so it feels very authentic.
You know what? You're absolutely right. I think I just absorbed the information from the first chapter where he prepared food for his mother and her cohorts (and she explained that she drew "erotic manga") and another mention in the second chapter about her career as a mangaka, and somehow remembered this information and connected it to Hamada. They may not be related at all.
Haru is that you!? (≧∀≦)