Hot take: this fictional character isn't canonically non-binary
I'm so tired of these annoying lefties correcting fans for not calling this fictional character non-binary. The author never specified what gender he actually is, therefore his gender is up to the viewer.
Like, sure, the dialogue always uses gender-neutral pronouns and explicitly avoids gendering her at any moment, but this doesn't make her canonically non-binary so it's just a headcanon. At no point in the story does she look at the audience and say "I identify as non-binary", therefore it's not canon. This is how fiction works, you can't expect audiences to understand things based on contextual clues.
And no, I don't apply this standard to other characters. If a character is refered to by she/her pronouns, it's obvious that she's a girl, she doesn't need to explicitly proclaim she is one. This logic only applies to characters who don't fit into the gender binary for some reason.
Anyways, stop ruining the fandom. Just because a character clearly doesn't fit into the gender binary, doesn't mean he's non-binary. Non-binary only happens when the author explicitly explains it to the audience like we're toddlers. And even then I'll just make something up to avoid thinking it's true.