Hard to believe a contractor in 2024 needs to have power on site to build. I rarely see a compressor on a jobsite anymore. The guns are either battery or gas powered, and most everything else is run on batteries. Most guys still run a cord to a miter or table saw but a generator can handle that. If they are dead set on using air, you'd think they'd own a gas-powered compressor for this situation, or at least rent one. Are you sure he's not just busy on another project and using this as an excuse?