I think it would be nice if more people knew how much social pressure stuttering adds in communication. Every day. It can be a topic people are very ashamed of. This is how it should be handled when talking about it. If they don’t bring it up they most likely don’t want to talk about their stutter. Nowadays I habe no problem if someone addresses my stutter. But my younger self was grateful for every friend who didn’t mention it and just listened to what I had to say. I think your approach is very good. Just wanted to emphasize how being careful with this topic is much appreciated!