I wouldn't bring it up, let him bring it up. And he is doing mental gymnastics constantly every minute of everyday just to try to speak clearly. He will bring it up eventually, you have to give him some time! :-) I am 44, and I also have a dad who stutters. I don't bring it up but it's pretty obvious. I figure that if someone (whether it's a job, friendship or romantic partner) can't accept the fact that I stutter, then they are not for me. I am happily married with two kids. It took me a while to bring up the emotional side of stuttering with my spouse when dating, and even with my close friends. For me, i feel ashamed when it happens, so that's why I don't talk about it unless I am very close with someone and can trust them.