so im in high school but for me ( and do keep in mind it reall just depends on each person about how they want others to deal with their stutter ) and im a more social person and talk a lot ( even with my stutter ) and mine is very very bad but it does effect me a lot daily though but if I was him ( and im not him so idk what he wants ) but i think it whould be nice ( also if you ever ask someone about their stutter make sure u keep a polite and nice tone ) ( proply am stating obivus but ye ) if you where to ask him if theirs anything you can help with ( tbh for me just having a friend is a lot ) and each person is differnt some dont mind if you help them finsih what they are trying to say ( me i like it so i dont have to seem like a idiot ) but dont do it every time bc then we get annoyed at you and ( I think at least ) that its ok to ask somoene about their stutter just make sure he knows that he dosnt have to say anything if he dosnt want to ( im also a freshman in hs so theirs the age diff to and I am in US so contry diff but this is all my opoion )