VH-TMP,
If he is prepared to persist then obviously he has dedication. Aptitude, of course, is quite another matter. Aviation history is replete with examples of pilots who repeatedly failed, or just passed, theory examinations but who, once in the air, became one with their machines and were very skilled pilots. This is particularly so in wartime, when pilots are required in some quantity, but it still occurs in less troubled times.
We all seek standardised tests on which to base assessments of an individual's suitability for a given task. For the most part they provide a reasonably quantitative appraisal but human beings are infinitely variable and not all are amenable to standardised tests, irrespective of ability or natural aptitude.
In due course, should the individual concerned finally pass his CPL(A), aptitude will be tested/assessed. The filtering process may not be perfect, but for the main part, it is effective enough.
I understand the road to a commercial career is far from straight, nor is it smooth. The CPL(A) is but a stage on the journey. If the person you refer to has both aptitude and dedication, he will emerge triumphant and may well make an excellent pilot.
If not, then the filter worked.