I think to call him employed could be an assumption too far. Many, many organisations have collaborations with experts in their fields to sit on panels, or do ad hoc work. Not all of that is paid, and those who are are more likely on a very modest retainer. Many expert panels will also have folks skeptical of whatever the approach is, to act as sense checkers/validators or even disruptors.
He may be fully paid up, full-time employed, but, personally, I doubt it.