Family attire

Hello! so my brother isn’t in our wedding, but of course he’s important (it’s a long story)
anyways, my fiancé, his groomsmen, my dad and his step dad all have the same color tuxedo for the wedding. My brother happens to have a tux almost the same color, if not the same color (I haven’t seen it in person) as everyone else. My fiancé and his mom think I should ask him
to wear something different and I don’t. Our colors are navy blue so the tuxedos are all that color. I understand my brother isn’t a groomsman but he’s family and just as important. Just wanting some opinions on my brother wearing the same tux color.