Well, to be honest, there were a few things that went wrong that day that were out of my control and as such we were in a hurry, so I forgot to brief him as a passenger, how the belts work and such, stay away from the prop.
Things he suggested were informing pax when you know theres gonna be some turbulence up head, for example we were going over some hilly terrain on a pretty hot day, its gonna be bumpy, let them know about it!! Coming in for a descent checking that they're seat belts are done up tightly, not just assuming they kept it on the entire time. Stuff like that.
And if you look at the testing form there is a section labelled "Manage passengers and Cargo" or it could even come under "Manage Pre and Post Flight Actions".
Personally I agreed with his determination, if I was in his boots I wouldn't want to be handing out CPLs to people that aren't able to manage passengers adequately. As he explained the flight itself whilst passable wasn't spectacular but the commercial considerations weren't there and added together he wasn't able to give me a pass at the time. Plus we weren't able to complete all the necessary parts due to some weather issues!!