Your client cannot e-file his 2011 return, Ranger, but must send it to Austin -- unless it costs less to send the hard copy to the IRS 'branch' in the US Embassy in Beijing. (I have a client in Denmark for whom it's cheaper to file his 1040 with the US Embassy in London, England.) If a 2012 extension had been filed (by June 15, 2013), he still could e-file 'this' year's return -- until December 16, 2013 -- as long as his AGI exceeds $0. (Zero AGI returns must be filed as hard copies -- Austin or Beijing or wherever.)
Don't forget, IRC Sec. 911 *also* entitles him to claim an exclusion from income for the cost of his housing -- above a certain threshold -- EVEN if he's not paid a housing subsidy. Do you know how much rent/mortgage + utilities + renter/home-owner insurance he pays? The *additional* housing exclusion is there in Form 2555 (page 3, I think), but not exactly obvious. I assume he'll file as a "bona fide resident"?
Which grade-level(s) does he teach? E.g., if he's a "primary-school" teacher, he's entitled to the $ 250 above-the-line deduction for out-of-pocket/unreimbursed expenses for school supplies.
Hope this helps, TaxCPANY