You probably don't need more power than the receiver can produce, but I don't know what kind of current demands this speaker may require.
Assuming that his receiver has pre-outs.... If he wants considerably more power, and the ability to drive virtually any load, instead of wasting money on a home hi-fi amp with substantially more power, simply get a Yamaha P2500S amplifier($400). 250x2 at 8 ohms, or 310x2 at 4 ohms, 20Hz-20kHz, both channels driven. If that's not enough power, then the P3500S($500) should be sufficient. 350x2 into 8 Ohms, 450x2 into 4 Ohms. These amps produce gobs of transparent power, but at lower cost than amplifiers sold for home hi-fi use. There is no difference in the sound quality. The pro-amps, however, are made better, to withstand more physical abuse, as compared to home amps. These are fan-cooled pro amps, but their fans never come on in domestic use: only when the heatsinks exceed 50 C(122F), do the fans start to activate. Typically, to make this happen, you need to be running he amps at very high power for extended durations - usually only possible in performances where large environment are being filled with sound. It does have pro-level inputs, though, and for ideal connection to a consumer device(consumer devices have much lower voltage output on the line signals), you would use an ART Cleanbox or similar. This device is simply an adapter that matches consumer to pro device connections for ideal performance.
If he wants more power, but also wants to spend as little as possible, the Behringer EP2500 pro amp($350) is a great amp. 450x2 at 8 ohms, 650x2 at 4 Ohms. The reason I did not suggest this over the Yamaha amps, is because it will need a slight modification for most home environments. The fan, unlike the Yamahas above, the fan in the Behringer is always on. It is also a loud fan. You need to swap it for a very low noise fan for home use. This is about the same difficulty as changing out the standard case fan in a PC case. It even looks like a PC fan and has the same kind of plug connector.
-Chris