Question. Is it ok to mention a person's stutter ?

Question. Is it ok to mention a person's stutter ? Like, to assure them that it's no big deal. I met a guy recently at work,he seems really interesting. Do I just pretend he doesn't have a stutter, or say it's fine with me,that it's no barrier to chatting? And, what do I do in the interval he's stuttering? It's quite a long delay. Do I keep staring at him, or smile and nod? And I'm sorry if this has been asked already, and I do not mean to offend anyone. Update: thanks. I'll be patient!.