There is no wrong way. Some people say it's safer to have them installed with the grounding pin at the top. The argument is that if the plug is partly out and something metallic falls and hits the prongs you could get an arc if the outlet is installed the conventional way. I'm all for safety, but that seems like an unlikely scenario.

If this is really bugging your friend, he could flip the breakers for the offending receptacles, unscrew the face plate and the mounting screws for each one, then rotate 180 degrees and reinstall. In most cases, there should be enough slack in the wires that he would be able to do the rotation without disconnecting anything or stressing any of the connections.

Hi - yes, he is perfectly capable of rotating the outlets himself, and will be doing so when he gets some time. However since neither of us are electrical laymen (but both of us have been involved in electronics/radio/computers for many years), it did "spark" the conversation.