Hi ya
My middle boy Rhys stuttered for quite a while it started as he joined nursery and we put it down to excitement, being tired and just wanting to get his words out faster that he could cope! We spoke to his teacher an we just made sure we told him to stop take a deep breath and think about what he's trying to say and see how it improved
We did this and it did improve and all stopped about 6months later (ish) if it hadn't we'd have gone down the speech therapy route I think,
I'd mention to HV see what she says also have a chat with his teacher and see if they've noticed it too they may have some advice as I'm sure they deal with it alot