Can 'them' be used to refer to one person

Yes, in a context like that.

Using "they" instead of "he or she" as in the case above has long been acceptable. "They" (and "them" and "their") are also increasingly being used and accepted as gender-neutral singular pronouns, even when referring to a specific person.

"Chris identifies as androgynous, so they prefer gender-neutral pronouns."

In fact, this usage of singular "they" was recently declared "wo

Great! Thank you both.

khoff even when referring to a specific person.

When the person's gender is known, I consider this to be illogical and a PC step too far.

Of course, 'Chris' can be short for 'Christopher' or 'Christine', so if you are unaware of the *** of the person referred to, 'they/them is more or less mandatory.

It's also useful if the person's gender is not immediately obvious -- if the person (either deliberately or not) appears androgynous.