bummer... I feel an ethics discussion coming on...
that code belongs to the company... can you contact the former employee to see about recovering it????
depending on how the data was formulated it 'MAY' (??? highly unlikely... but maybe) possible to alter it. If, for example, he kept a directory of queries used to formulate result sets for display there is a possibility that you could alter the sql content of the query file... or if by some chance he used a query or stored procedure on the server then that piece, potentially, could be altered and might alter the display in the exe... but only if he didn't define the 'fields' in the grid or table objects via the field editor... if he did then you're hosed.
most likely he has got the query all wrapped up in the exe and there will be no altering it.... but you might get lucky... use extreme caution... if you break it it's game over.
Some languages (and language families like .NET) make it easy to recover the source code from an executable. Delphi 7 is not one of those languages. It compiles down to real object code, which is fairly well optimized after it is generated, so getting source code back is pretty difficult.
Is there any chance that backups of the source code are available anywhere? Could they be on old network backup tapes?