I take fundamental issue with the idea that a single metric should be sufficient to disqualify a student.
If papers and research are exemplary, I see no reason that exams should disqualify someone from obtaining a Doctorate. The bar should be somewhat higher, but not to the point that the only way you can get a PhD without passing all the exams is to win a Nobel.
I don't know how well that applies to this specific case, however.
I take fundamental issue with the idea that a single metric should be sufficient to disqualify a student.
Typically, other than exceptional cases, usually there is a bare minimum requirement to meet(on some criteria or other) to avoid disqualification. System needs its rules to run efficiently.
If papers and research are exemplary, I see no reason that exams should disqualify someone from obtaining a Doctorate. The bar should be somewhat higher, but not to the point that the only way you can get a PhD without passing all the exams is to win a Nobel.
I don't know how well that applies to this specific case, however.