In English, the use of he, him, or his as a gender-neutral pronoun has traditionally been considered grammatically correct and suitable for this situation. Learn English, please.
It’s not. They is the gender neutral pronoun, and it’s much more socially appropriate and polite to use it in situations. In general just don’t use gendered pronouns
Non native English speakers here.
Using they as sigular really confusing to read.
Oh yeah, also this...
Blame the people who helped create this language who never saw the need for a neuter singular
I don't care about your murrican culture. I was happily reading when I got stuck and confused when I read "they". It's too unnatural there. Author did not intended it not even that character would say it. For Jinguuji, Tachibana is guy and is determined to make sure he gets his body back. At the moment Tachibana has even male body. It's only natural for Jinguju to refer to Tachibana as he. In case when Tachibana has female body I can imagine Jinguuji feeling uncomfortable in front of others refering to Tachibana as he or she so he would just use name. So in conclusion since Jinguuji is just thinking Jinguuji would use "he".
Native speaker here, they is correct, and actually just more of a general thing; ie “they(singular) said that the pizza was arriving”
Unfortunately they is both the singular and plural neuter pronoun for English, so if you want to use gender neutral language, which you should, they is the polite way to use it. It exists, but it’s incredibly impolite as “it” implies that you are referring to an object
The way you separate from plural they and singular they is context.
“My friend is bringing pizza for their birthday, they like white pizza, so we’re getting that for them”
“John is a boring person, they never talk about anything interesting”
“Jane is a deer hunter, I wish they wouldn’t, but I can’t stop them”
This is typed, and on my phone, but wherever possible, it’s best to use the neuter they/them as opposed to otherwise