I suggested getting him a Lumia 521 but do not activate it. The basic function he needs is opening a spreadsheet, updating his inventory and then plug into his PC and save that spreadsheet to their network share.
I was wondering what everyone else thought, will the 521 function without an activated SIM? The existing device doesn't use wifi, and we have policies against putting unmanaged devices on wifi, so that's not a problem.
Also the fact he was on WinMo6.0 (or 5.something) caused him to be stuck on using old style XLS spreadsheets and putting him on 8 will be the easy migration path for going to XLSX.