I bought a pair of 48 spoke tandem wheels from that vendor a few years ago. The spoke nipples were supposed to be brass, but mine rusted. I replaced all 96 personally, so was a good, but tedious, experience. Other than the spoke nipples, the wheels have been fine. I do recommend that your friend learn to test and adjust spokes to ensure roughly even tension throughout the wheel otherwise spokes will break when under loads and hitting bumps. That's probably what occurred with his original wheels -- lack of even, roughly, tension across spokes.
P.S. Yes, I would buy from that vendor again, especially with an auctioned set of wheels that could go for much less.