Just for future reference...
There is such a thing as DelRep--Delay in Reporting.
If the school is in shutdown mode at that time he is to report, he will likely just report to someone on duty and wait. If it is possible, why shouldn't someone have the option to be someplace else during the "off" time? This could allow a savings in airfare for the individuals who ask for this privilege ahead of time instead of reporting and leaving from there to go back home and then back again.
The important thing here to know is that the current chain of command has no obligation to arrange for this.
The person needs to get the FTS or Federal Telephone System number for the director of the school. Then, he or she needs to have compelling reasons to be DelReped. Once DelReped, he or she can get a new report date that will have them arrive in time to class up and will receive a followup telegram to the address given the granting authority.
If the telegram doesn't arrive, the original date will be invoked and you will be UA and on legal hold, no matter what was said over any telephone when you arrive--the telegram is your amnesty. So if authorized DelRep, always have plan B ready (i.e., reservations for a flight that will get you there on the original due date).
If you ask how I know, I will have to take more time and space.