If a student has been on an Integrated course and does not continue as an Integrated student after the groundschool phase and exams, for whatever reason ( personal, family, financial), then their exam results will be valid for issue of a CPL/ IR, provided that is within 36 months of the end of the last exam. That looks to be the situation in this instance. He can now continue Modular.
The next step is for him to do his PPL. He will not have to do the PPL ground exams, the ATPL level passes will be accepted. Saves him wasting a few hours doing the PPL ground exams on morning.
After that he needs his 100 hours PIC, and any extra to get the 169 hours required prior to starting a Modular CPL/MEP/IR course.
In other words, the ATPL exam passes cannot be revoked just because of a change of route.
Doing all the ATPL exams "up front" has its downsides, but it does save wasted money and time on flight training if someone is going to struggle with, or just cannot pass, the academics.