I'd be interested in what he says. I'm a different kind of engineer, but in school all engineers are encouraged to bet some exposure to other engineering disciplines, so I can at least give you some background.
Not all oils are petroleum products. As you point out, olive oil is not petroleum.
But they are similar. Very similar.
Petroleum is just a common, handy, and inexpensive source of the carbon & hydrogen "building blocks" that are taken apart and reassembled to make everything from gasoline & oils to plastics, asphalt and beyond.
You can do the same by starting with olive oil. Or for that matter by starting with a gas. Natural gas is particularly good for that.
What is different is the type of process used for splitting and recombining the building blocks.
Enjoy your time together,
rScotty