PVT Ops.
read Sasless's post.
"incidental" to the job.
Think of it as the house and forklift belong to builder. Builders bricklayer can drive the forklift but thats not his primary job just like most people can drive a car or truck.
Maybe this guy was the accountant or something, if NOT, it's a big problem.
The operation would still be Part 91 but you need an FAA CPL minimum.
The FAA these days will only give you a "based on" validation to PPL level. Otherwise you have to meet the requirements of a full CPL. Pretty common arrangement around the world.