All homes are wired with neutral wires. Older homes, usually built before 1970, often do not have ground wires going to outlets and fixtures. The ground wire is either colored green or is bare copper. It was added as a wiring requirement in most jurisdictions before 1970. It provides a means of safely grounding the case of appliances to prevent shock in the event there is a breakdown of the insulation within the appliance.
All homes have neutral wires.
The Neutral is the return path for the current going to a light or appliance. It is normally colored white. It will always be present at the appliance or the light fixture. It is usually present at the switch, but not always. If he uses the switch leg method, electronic switches that require a neutral can not be used.