The Swedish gender neutral pronoun hen has a lot of controversy around it, as divergent responses here on Quora show:
- How has the gender-neutral pronoun experiment in Swedish worked out so far?
- Is the creation of a gender neutral pronoun such as “hen” in Swedish considered semiotic warfare?
- What are the official recommended object and possessive forms of the Swedish gender-neutral pronoun hen?
- Why did the Swedish succeed in reforming the language by adding a gender neutral pronoun “hen” when English speakers failed?
So: not necessarily as well as you might think. In fact, English they/them has an advantage over many languages’ attempts at gender-neutral pronouns: there’s linguistic precedent for it (though it was as a non-specific, rather than as a primarily gender-neutral pronoun)