I think it depends on the person and how bad it is im only 15m but my stutter has effected my social life a lot ( have like 1-3 friends and never have dated so ya but for me at least if he starts to stutter just contiue what you where doing and treat him like a normal human and give me him time to get it out no matter how long it takes ( for me at least it really makes a differnce and it makes me feel valued as a human ) but you best idea is to ask him about it and if he says no about any quetions you have dont push ( keep in mind this is all for me so Idk about him ) and if someone starts to talk about him ( behind his back or not ) for his stuttering stand up for him and defend him ( he might of given up on stoping it but it shows that you care if you stand up for him ) ( i can try to help if needed but it probly will be best to ask everyone else on here to for a bunch of differnt sides and experiances )