Depends upon your outlook, but remember there is no requirement to actually have a valid medical whilst undergoing training. This therefore, means you can complete the training elements and then once the medical issue is resolved finish the hour building and skills tests.
Depending on his total hours at the moment, this probably wont help him, under EASA Part-FCL Appendix 3, requirements for the CPL are:
3. Before commencing the flight training the applicant shall:
(a) have completed 150 hours flight time;
So if he doesn't have 150 hours, he would need to fly dual to build time to start the CPL course, even doing the IR first this could still be a stretch. Then
12. The applicant for a CPL(A) shall have completed at least 200 hours flight time, including at least:
(a) 100 hours as PIC, of which 20 hours of cross-country flight as PIC, which shall include a VFR crosscountry
flight of at least 540 km (300 NM), in the course of which full stop landings at two aerodromes different from the aerodrome of departure shall be made;
So he would still then need to build up to at least 100 hours PIC in order to apply for the CPL, albeit this could be done post-test, but the application needs to be with the CAA
before the 36 months on the exams expires, or they will reject the application and he will have to redo the exams and the CPL course.
Unless he could get some sort of approval to fly as PIC to build the hours with a safety pilot for medical reasons, then his only hope is an extension on the 36 month limit for the theoretical exams.