Does Yon Mate smoke or will there be a lot of smokers around. Some cheaper PV kilts will go up like petrol and I once saw a PV plaid go up in smoke at a wedding from a candle bump.

Do your home work first when buying. I would think Irish National/Heritage may be best if he is of Irish decent. This would make him feel comfier in a kilt. Rather than wearing an unrelated Clan tartan.