found he was only qualified as a co-pilot,
Could easily be that he just pencilled in enough hours to get issued with an ATPL, and had the chutzpah to apply for, and the luck to land a P1 job. Sure he'd be uncomfortable then, and soon get spotted.
The word "qualified" would seem to support this, because he clearly passed the company induction and sim checks, and then worksd for several months. If fsubsequently found to be only a CPL then "Not Qualified" would be the word usd to describe it, not so?