Actually, he claims to have a "medical category". If his claim is taken at face value (and his obvious 'attitude' is overlooked) then it is likely the documentation surrounding his medical condition is more extensive than simply a "chit" saying no shaving. However, having a medical category (with the specific MEL he states) does not automatically grant him immunity from any future familiarity with a razor. Whatever he does to avoid shaving is probably going to p*ss off his Pl 2IC, so if he wants to press the matter he should request that the order to shave be put in writing and copies placed in both his pers and medical records so that "he is covered medically in case there are any adverse reactions". Now, if such a request were to trigger a re-evaluation of his medical condition, there is a possibility that the category could be made even more restrictive - to the point that he is undeployable, thus unemployable, thus releasable.