Lots of things can be used but just to give a run down of the typical type of lights for painting a car:
A torch/phone torch: being small sources the light sources are quite 'hard'. Typically you'd want something a bit softer as its easier to shape the car. They typically also lack power.
Torch in a softbox: take a regular softbox/strip box and shine your light through to negate issues above.
A light stick: What I have used in the past - an Icelight (see profile pic) which is expensive but there are cheaper versions that do the job too e.g. Yonguo/Pixelstick etc. You can use barndoors as well to really get the light where you want it and avoid spill (such as lighting yourself in the shot- little tip dress in all black when lighting a car).
LED video panel: the typical panel LED's used for video lighting. Works well and is typically what I've seen others who are starting out use.
If he's just starting out, I'd recommend he practices on cars with bright coloured paintwork so its easier to see what he's doing in terms of shaping the car etc. Black cars have a different approach and are a bit more complex.