Q:the person whos friend is trans and referred to them as she, they could be a transfemale who is binding HRT breasts for safety/coverage?
K: It’s certainly a possibility, yes, as well as the person being NB identified. There are a number of possibilities. As others have said, we don’t know the preferred pronoun of said person, so we can’t assume. But the asker is trying to educate themselves on trans* issues by not only following, but asking questions they are curious about and they should be recognised for that effort.