Hello, and a warm Celtic from Boston, Massachusetts. An evening dress or gown, with a touch of his tartan used as an accessory, will steal the show. A long time ago (high school) my girlfriend made an evening gown of the same blue as is in my clan tartan (MacNeil of Barra, ancient) then made a shawl of my clan tartan that gently fell in an "X" across the front with a brooch holding it together. This was worn to several formal functions, she always stole the show.
Slainte