Err, HP have another look at LASORS and you will find that the Military QFI concessions to which you refer are only for those "...having been tested by a CFS Agent and granted a Certificate to Instruct on single pilot, single engine piston powered aeroplanes within the 12 months preceding receipt of the application."
Since I doubt very much whether this would apply to our FJ mate, he would need to follow the LASORS guidance requiring him to complete training at the discretion of a FIC Instructor at an approved FIC FTO (i.e. 'Assessment at an FTO') sufficient to pass the relevant elements of a FI Skill Test in a single pilot, single engine piston aeroplane with a suitably qualified civil FIE(A).
He would also need to hold a commercial licence to receive remuneration for any PPL level SEP training. Which includes, of course, holding a JAA Class 1 medical. For non-remunerated instruction, a PPL with FI rating is sufficient; that only requires a JAA Class 2 medical.