I LOVE that you're considerate of your coworker's feelings and treat him like anyone else. Thos are two incredibly important things you've given him. Honestly, it could go either way. Not everyone feels the way I (36F) do, but I prefer when someone brings up my stutter so I don't have to. I'm totally fine talking about it as an advocate but not a museum display, and if someone else brings it up I feel less like I'm unsolicitedly beating them over the head with what it's like to be a person who stutters (PWS). I've found that opening up to people about something so vulnerable and intimate makes them trust me more, encourages them to show me theirs, and generally leads to deeper, more meaningful conversations and connections. And it definitely alleviates the pressure of feeling like you're hiding or avoiding something that everyone else is keenly aware of. I also open that door for other people so they know I'm fine talking about it. I'll acknowledge my stutter when it happens ("My stutter always gets worse during allergy season"), or I'll cite it as a contributing factor ("My stutter was so much worse as a kid but I still hate public speaking") so it's relevant and not a super awkward moment for everyone. I wasn't really comfortable talking about it until I started going to speech therapy at 30, though. And everyone's on their own journey with different timelines. I've only met one other PWS, and I will say that he jumped at the chance to talk about his stutter with me (though it is different finding someone who's fluent and willing to listen vs. someone else who lives inside it). My gut instinct is to encourage him to talk about it, especially if you're close and he's mentioned it before. Maybe ask how his son is doing and see if he mentions his stutter again. Or watch him for cues: If he physically reacts to his own disfluencies (if he winces or looks annoyed with himself during/after he stutters), it's probably something he's still fighting and is maybe best not to address 'til he brings it up. I wish I had a more definitive answer for you, and I'm sorry I don't. But I think the most important thing you can do is keep treating your coworker like he' s anybody else and be a good friend. Which it sounds like you're already doing.