Couple of issues here.
- Leave program is a Commander’s program, the Commander can deny leave for what ever reason he/she desires. It is on the Commander to justify their decision should an investigation, IG, or Congressional inquiry be made.
- Since you are in the med board process, part of the command’s responsibility is to ensure you are available for the evaluation appointments during the physical evaluation phase. Depending upon where you are in the process and the times/dates for block leave. This may be the reason the Commander has denied the leave.
Soldier could use the open door policy to inquire exactly why the leave was denied and if an alternative time to take leave after the evaluations are complete is an option.