From DS2026 experience, CFA is pass/fail. If your son passed, he should be happy and move on. Academics get a higher overall score so he should focus on the standardized tests (retake as necessary to increase section scores).
Also complete the MOC application, deadlines to submit the package should be happening soon.
For the interview, he can ask his interviewer for feedback. DS did this with his squad leader cadre, but it was virtual SLE via remote conferencing and emails. DS got positive feedback. Anyway, he had another interview with a local FFR (a retired Colonel) which was in-person - it seems this one counted more and seems to be required during his application regardless of the SLE interview. He was told the SLE results do not affect his actual application - not sure what that exactly meant. He didn't ask. Hope this helps.