I would not refer people to JW facts b/c they will believe the letter is a forgery. What I would suggest is telephoning the UN myself, get the appropriate department and make certain that they will confirm that the WT is an ngo. If they will do so, have the Witness call the UN himself so he can hear someone answer, "United Nations,........."
I loved the UN growing up and kept going on tours with my family. My dream was to be a female tour guide. They were so attractive and so not American. An adult friend worked for the Council for Namibia before independence as an international civil servant. He was an American Jew and had some interesting experiences. When Pres. Reagan was shot, professionals stood on their desks and applauded and cheered.
I had to keep my wish a secret. Well, even if I were not a Witness, foreign languages are not my forte. This do as I say, not as I do and lying has me furious.
Whenever I toured or visited my friend and saw some private places, I never saw any beasts roaming around or any weird number cbominations.