Whats your best advice for a toddler who might be in the beginnings of stuttering?

Whats your best advice for a toddler who might be in the beginnings of stuttering? I suspect that my 3 year old nephew could be in the beginnings of stuttering. How should his parents deal with this matter? Is it best to ignore it for now so they don’t make it a “thing” in his mind? Or should they take active measures at tackling the issue (like therapy)