I saw your question from the front page. I hope my two cents help.
A lot of people can work for the Department of Defense. He is a linguist for that job.You don't have to be active duty.
To rent to active duty personnel is more guranteed than renting to civilian. Ask him for his firt shirt's phone number and ask about him. Those who are active duty normally won't or dare not miss their rent, otherwise they are in deep trouble.My hu*****and says you don't have to worry about that. Plus military people follow rules. :)
ETS是June,2014 means that he'll stay active duty until then unless he signs on again, not necessarily means that he will stay there. Only draw back with renting to military people is if he receives order and has to move, you'll have to let him without penalty.