Unfortunately, most of the time, clients have no idea what they're talking about.  For any client with any sort of equity compensation I always request the year-end paystub.  Sometimes they're cryptic but once you decipher them, they're a gold mine of information when you're trying to unravel this stuff.

If the employer did not include this, then he really needs to go back to the employer and get it fixed.  Either the 83(b) was not properly filed (which likely makes it invalid), the employer did not properly communicate with the payroll provider (need a W-2c), or the employee misunderstood what actually happened.  There's no way I would use the PS Wks to add compensation in this circumstance.