the [very common] problem will be in the shifter box on the column - need to manually move the arms that come out of it to get it back in neutral, shouldn't require disconnecting anything - make sure you're on level ground and there's no driveline force on the trans or have someone hold the clutch in and the brake on ... your neighbor made a sloppy shift just before he stopped, but it indicates you need to give that box some TLC
Bill