a finish nailer is for doing trim work inside like window surrounds and baseboards and cabinates.
a framing nailer is for nailing large nails to make the structure of the house.
if he isn't building houses then a finish nailer (also known as a brad nailer) is good for projects.
and he can always upgrade later to a framing nailer to go with the compressor.(if the compressor is large enough for a framing nailer). unless you already have a compressor.
there are also nailers that run on a power cell and a battery. great for those small jobs that you do not want to bring out the compressor for.