I think the question is: does stop loss apply to the inactive reserves?
If he attempted to resign his (reserve) commission in June, then there really is no reason for him to be called up.
On first glance, I'm tempted to side with the Captain on this one. That is assuming stop loss does not apply to inactive reserves, and that he attempted to resign his commission before he was notified of activation.
As a sidenote, I know it may seem unfair that officers can resign their commissions after their commitment is up, and the enlisted have to wait out their enlistment - but that is how it is and has been for 200+ years.
Noone, no matter the critical skills has a lifetime obligation to our military. Once the contract is carried out
and the eight years of total obligation is full filled one
is home free.
Military duty is not a lifetime sentence.