Fireface is a great audio interface with very nice convertors for the money. The pre-amps aren't interesting tho, don't but it for them. They still can be ok for some extra pre-amps maybe tho.
Pre-amps: look at Sytek, 4 pre-amps in 1U, take the Burr Brown option on channel 3 & 4 for different sound options. That will give you 4 good pre-amps in addition to the 4 'not too special' RME pre-amps. Maybe save up and add a 2channel 'money-unit' of choice to this (now or later), then you'd have 6 good pre-amps, and 4 RME extra 'for in case'.
Convertors/souncard: Fireface800
Software: Nuendo 3 will be overkill probably. Cubase SX will do fine and works the same. And you'll have no problem loading his Cubase sessions in your Nuendo. The money you save here, you can spend on the more high-end 2channel pre-amp.
Of course, if you wanna start out cheaper, the Presonus Firepod ain't all that bad: decent convertors and pre-amps, plus it comes with a small version of Cubase which will be enough for tracking purposes.
Cheap computer: any PC is cheap and fast enough these days. Be sure to use quality components. Don't skip on those to save just a few 100's.
Headphone distribution: lotsa cheap choices here, even Behringer would work
Active monitors: again, too much choice, depends heavily on his budget and taste.
Plugins: If he doesn't do mixing (ie, you mix his stuff), he don't really need the addition plugins.
Mics: get the usual suspects: D112 for kick, SM57 for snare (maybe also an MD421 for some options), 2 SDC's for OH (AudioTechnica 4041, Studio Projects, ...)
Monitor unit: Presonus Central Station or the SPL unit, or Mackie Big Knob if it ahs to be cheaper.
Not sure if this is all in the planned budget, but i hope it helped a bit
