What I use:
i3 3220
Gigabyte B-75M D3H
8GB Corsair RAM
m-audio Delta66, e-Mu 0404m and a Xonar D2X
Radeon HD6450
256GB Vertex4
WD640AAKS
Seasonic S12ii 430
Antec Solo I
I would definitely stay away from this specific motherboard. Almost any other H77/B75/Z77 chipset board should be considered.
And Haswell. The power management is not playing nice with DAW apps. Not at all recommended. If you can't get IVB or SB, opt for AMD instead.
The way to go for DAW setups is to work out your audio interface choices, and then plan the rig around that. If you use a USB interface like one of the new Focusrites, then the rig can be most anything as the inboard latency is swamped by the latency of the USB bus and the device drivers.
The CPU is marginal in the DAW performance stakes. It is rarely used while recording or mixing, only when calculating and applying effects. We come from an age where we could do upto 32 tracks with effects on a Pentium II, so if your bro has some idea of submixes etc he will not need to worry about CPU power. The i5 3450 is an excellent choice if you feel you have the budget.
What you do need is good amount of memory. More memory = more tracks, lower buffers and is generally a good thing to have 16GB, though basic setups like mine get by with just 8. And a nice low-latency motherboard. Intel usually is preferred by DAW professionals because of the tighter latency, regardless of how poorly they are hobbled in terms of BIOS etc.
Next, get silent fans and a really silent PSU. I can't stress this enough. The Seasonic I use is not whisper quiet, but my condensors can't pick it up from a few feet away. The case fans are usually switched off while recording (I do this manually, by removing their headers). The CPU is cooled with a Deepcool 400XT:
www.frostytech.com/articleview.cfm?articleID=2621 It's really important that fan noise not be picked up by a mic, which are really sensitive to both the hum and vibration and the blade pitch. This is an excellent cooler when left to a low speed, almost inaudible outside the case. Which brings me to the final hardware issue, that of the case. You have to get a case that does not let sound out at all. Even at the cost of a higher system temperature. For audio, Antec makes some excellent silent cases, though they tend to be expensive. The SoloII is a great case, if you can find it. CM, Corsair and Bitfenix all have some silent offerings, though for most of them it means a leaky case with soundproof cladding and anemic fans. Antec is really the only company that knows about thick steel, quiet mounting of drives and proper fans that can still cool at low RPM. Even in a control room setup, audible noise is an issue while monitoring and critical listening.
Another note is on software, most of the really good DAW programs run best on XP, with 7 providing a bit of performance degradation. 8 is not yet recommended, again because of power management which cannot be fully overridden.
If your budget includes the interface cost, it's pretty tight. You can drop down a few levels on the platform (AMD Sempron will make as good recordings, but it will take longer), but don't compromise the noise factor or the quality of your interface. Your motherboard will be obsolete in 6 months, but a good case, power supply and a good interface will last you ages (my Delta is 12 years old and going strong, my Antec case is in its 8th year). Fans unfortunately you have to change every few years as they tend to age noisily.