Ive got an R33 GTS4, had it for a year and a bit now, and ive had not one bit of trouble with it. Hell if he's looking for a coupe why not go the sedan, there good looking, handle as well, and yourve got 4 doors for your drunken mates to stumble into!!
Parts are easily accessible, and a decent price, Im talking bout parts for servicing/maintainence.
Fuelwise there like most other cars in their capacity, if you flog them, they will drink fuel.
Handling, boy o boy, what a step up from driving a Mitsu express Just kiddin, they handle like a dream.
If he's young too, the skyline is a very easy car to do some minor "rice" mods.
If your nephew wants one, i say go for it, if you dont go and own one today, you might not have the chance tommorow. But as always. Check out the car, run it through inspection ect ect.
Goodluck in your search.