I should add that while I am not a lawyer, I am The InfoSec officer for my organization and by handing them his hard drive and asking them to recover the data he effectively gave them permission to look at every single bit of data on the drive.
On a technical level, regardless of whether one is using a software package designed for this purpose or if one is doing it by manually reconstructing the files, the tech would either be looking at the bits that make up the data or their software program is looking at the bits that make up the data and determing what bits are parts of which files, then putting the bits back together to recreate the files. Of course, that's looking at the ones and zeros, but you're viewing the data as a part of recovering it.