I am American (or at least was, I emigrated away) and will use the names of my family members to people who have asked about them and I have mentioned the names

I am American (or at least was, I emigrated away) and will use the names of my family members to people who have asked about them and I have mentioned the names before. Using them without ever introducing them sounds very strange (nothing to do with casualness or whatever, you would just have no way to know what I am talking about.) I suspect they think they have already mentioned them before, but forgot they didn’t? Or are you saying it is weird even if you know their names to refer to them by name?