Question to those of you who use pronouns

Can you please help solve a minor disagreement I have over this with a friend

When do you starting using “they” or similar pronouns when speaking to or corresponding with someone?

Background:

It started last summer when we held a seed exchange at a local park for our community group we started years ago. A guy from our group showed up with long hair, both ears pierced. His name is Jer short for Jerry. Jer was so sweet that we talked about how nice he was after he left. Jer lives with a lady and they have two kids. I kept referring to Jer as him/he but Kerri insisted we use the pronoun they.

to me, Jer just looked like a 1970s hippy but Kerri said that because he has both ears pierced and she noticed some feminine characteristics (which I did not) that he would be someone we would use pronouns for.

The disagreement is this. I say that we should not assume someone wants us to use pronouns and Kerri disagrees and says if they look like they could have characteristics of both male & female that we need to assign the “they” pronoun automatically