Procure for him a white suit at Portabella Clothing stores. It will work just fine as far as Kabbalistic issues of white & not black clothing for Shabbos goes.
Based on Kabboloh:- No-one should be wearing black on Shabbos, as this is connected to Saturn>>Saturday which is a black Avodo Zoro, which according to Kabbolo will end up sending one to Gehinnom for wearing black on Saturday. …. If anything, one should Davka wear 4 white items on Shabbos {to do with letters in haShem’s Yud-Kay-Vov-Kay Name}. Other than these 4 white items, any color other than black is fine for the rest of one’s Shabbos attire.
Hence this problem of black clothing wouldn’t apply to a weekday Yom Tov.