Just how big is your boyfriend if 7ft is a shortboard to him? Erm from the way you've desribed his surfing both waves, skill and time on the water i would be expecting him to be riding something around 6ft 2"- 6ft 4" in length.
Still anyway, depends where you get the board from. If you get it from a shop you can always take it back if your boyfriend decides he don't like that one.
But remember a surfboard is for life not just for xmas.