Indeed, the spreadsheet I am thinking is particularly hot garbage, but slap some dorky corporate bar-charts on there and it's like beer-googles for suits.
But why are you associating that with Excel? Every analytics tool features charts front and center regardless of how it is delivered, web, BI, dashboard, Jupyter, etc, and no matter what language it is written in (R: ggplot, Py: matplotlib, JS: highcharts etc.).
The guy's spreadsheet seems to work. He's delivering what his bosses want to see. You might have an issue with the final output but they apparently don't. What exactly is the problem you think you can fix?
I am on the side of excel being used like this, even if it's hot-garbage. The worst that can happen is that it collapses upon itself and then others need to come in and do it right, or migrate the thing to something else entirely.
The guy's spreadsheet seems to work. He's delivering what his bosses want to see. You might have an issue with the final output but they apparently don't. What exactly is the problem you think you can fix?