He is NOT eligible to file I-485 UNTIL the priority date is current. It is currently taking about 10-12 years for the priority date to become current for this preference category. Until he is eligible to file I-485, he does not qualify for any work permit. In fact, he cannot just remain in the US if he does not have an independent nonimmigrant status to do so.
Answered on May 03rd, 2013 at 3:36 AM