[BrandoElFollito]

You mean that you say "do they want some chocolate" when directly asking that single person if that single person wants chocolate?

I thought that "they" is too ne used instead of he or she (3rd person) - which I find useful to avoud he/she or (s)he

EDIT: I had an epiphany under the shower, sorry I misunderstood you and you probably meant that you now have to say "ask your friend Jane if they want chocolate"