Super slim foot, are rather large

I bought my son the shoes for school sport and am very satisfied. He has very narrow feet and found in most sneakers no proper maintenance. We've also had last year a similar model of the KangaROOS very good fit and well with these sneakers are doing great.
Important to know: The sneakers fall probably from rather large, I have both the first pair, as well as ours bought a size smaller than my son wears regularly. The shoes in his size had still well behind an inch air.