I had a similar thing going on with a clueless manager. He wanted an explanation why projects weren't getting completed on time. I suggested I could do one better and show him why. He agreed. I downloaded I think it was a sample SAT math test. Where ever I got it, it was one of those four or five hour timed math tests.
I gave it to my manager and told him it had to be completed that day. And that just a passing score wasn't acceptable. It had to be returned at 100 percent. No exceptions. But the good news, it was open book. When completed, at his discretion, he could go back over any or every answer and double, triple check, use Google or whatever he wanted. But that no matter what, 100% was needed.
I handed it to him and said your time starts now.
Then I continued taking and mentioned the two meetings we had scheduled. I also told him I'd be needing his help later that day solving an issue we had with a project that was also due that day, etc.
I said I'd be back at the end of the day to see how well he did accomplishing his basic minimum job requirements. I wished him good luck
My goal was to convey that programming is like taking a math test. A math test requiring 100% accuracy. A task requiring full, uninterrupted concentration. That checking every answer when finished was equivalent to testing the code. Even if it was similar to taking the 4 hour test several times. But along with that, meetings, telephone interruptions, being pulled off on unrelated tasks were all part of the job.
Did I mention he was a little clueless? By the end of the day he hadn't even started the math test. And yet he never seemed to 'get it'.