Back of coat buttons should go higher up, as those are meant to cinch the waist. Wrist cuffs should come down closer to where wrist flares into the hand, or the cuff of the shirt being worn under the jacket should show. Wrist cuff buttons more towards back of hands so they won't drag when he's resting his arms on a table. Colour combos and various diagonal lines look great! Poppee collar without any hint of shirt, tie, cravat, etc. underneath makes him look like a but of a chad/tool. If that's part of his personality, keep it.
Boots are way too tall for formal AND ass kicking purposes compared to current day. Those stompers make sense on a goth goggle wearing scene kid. Maybe instead look up some intersection of sports and military with men's fashion for shoes, and choose jeans with some baffling style of stitches to hint that they're reinforced with padding or something? Beware making the pants coloured or he'll begin looking like a stunt motorbike guy.