I’d just refer to them by their name at all times and not bother with their ‘pronouns’ at all!We have just had a non binary member of staff join our team, it's exhausting, your brain has to be one step ahead when discussing thier training needs with the boss and other team members. Getting the pronouns correct is bleeping hard work - we have not even got to the stage when we have let them loose on members of the public yet. Our elderly clients who will no doubt not understand they are not she/her and will take offence to being corrected with they/them. It's already a bone of contention they appear on the teams shift rota as their given name and not chosen non gendered name but as they have not changed their name legally their name has to be their birth name as it's linked to payroll and the name they are registered to pay tax under.
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It’s not fair that everyone else has to buy into their delusion.Serves HR right for taking a cv with pronouns on it or continuing an interview once the views on mishearing were found out. They will cause nothing but trouble. Keep a record of things they refuse to do and ways in which they sow disharmony. It’s not fair this person has been imposed on you with all their special rules and beliefs.