@Fari
Well I know the slightest bit about japanese and english (it's not even my mother tongue) and it doesn't bother me at all tho. Also I don't expect perfect grammar from fan-translated stuff.
From my pov, you guys are just allergic to japanese despite being fan of manga.
Anyway, in this...
You guys might say that but in japanese when people talk about somebody without revealing the gender they mostly use "ano hito -> that person".
So it literally the correct translation.
Stop teasing and read that fucking book already...
That book is the only plot-related thing in this story and the author is dancing around it without touching it.
I'd bet everything the book gonna be stolen before MC even open it.