No, it's not. The only law that requires an employer hold a job for military service involves members of the Reserves. If a Reservist is called to active duty, even if it's just for annual training, their employer must, by federal law, hold his/her job for them so they may resume their employment when they return. Enlistment in the regular forces is not covered by this law, so as soon as your son enlists and leaves, his old job is gone and the employer does not have to hold it for him.
