As far as I know from the pre-serialization, and the little bit of this that's been tl'd into en, he's basically someone she just met when feeling down. I don't believe it was explicitly stated in either (as of yet anyway) though I'd need to reread the last chunk of chapters to be certain I didn't miss a detail months ago- but I'm hoping to see a couple more new tl'd chs and then start a fresh rereading of it from the start again.
this is becoming too much of a trend now : everytime a small awesome twitter like manga gets serialized, it loses the soul that made it great in the beginning. The relationship is weird now and characters are different... :/
@Ank probably cause Twitter stories are made to last whenever the author wants but serialisations are made to last for a long time so the story has to change to fit that.
If you like delusional fujoshi side characters, stick with it. I preferred the "gangster househusband" manga for the gag setup this manga uses (of heavily suggesting one thing and doing another).
I'm so glad this didn't take a weird turn 😭 turns out he really IS just her uncle.
Spoiler? for those who are worried that it would be a weird thing?:
Ayumu's dad is a close friend of his, since he knew he was dying soon, he entrusted him to teach her to be more irresponsible/relaxed, the same way he taught him. There's no hint to him wanting a romantic relationship with her AT ALL.