My friend called & asked me just now why his wires are hot while the breaker is off. He just installed a new 200 amp panel which was inspected & passed. I am thinking maybe the neutral is hot? He says when he turns the breaker off, the lights go out but the outlet is still hot. I am not able to go there to see for myself so... any ideas??

Have him use a hand-held tester in the outlet, with the breaker on and then off. This will tell him if the hot & neutral are reversed. Also, just a guess, but perhaps there is an error in the wiring of the branch circuit such that the hots from two different breakers are spliced together somewhere? If he has a handheld voltmeter he can check for voltage at the output of the circuit breaker with the breaker in the off position.

That neutral may be the neutral in another circuit too so it can still carry some current. You just never know how folks have wired your home until you start taking it apart.