Yeah i mean he would be fine with a 850W but because all cost around the same as that 950W i would get it.
He'd probably be fine a 800w too imo. Two 7970s would draw about ~580W under load. Add another ~200 for an over volted 3570K, throw in a couple of fans And Hdds he get up to about 800W.
Edit 2: If cards are OC'd. So I was wrong, You'd definitely need a 850w min for that.