How long it would take to get work authorization?

Generally, a U.S. citizen may sponsor a sibling for immigration in the Family-based Fourth Preference (F4) visa category. There is a very long backlog for visas in that category, however. The October, 2017 Visa Bulletin issued by the U.S. Department of State shows that visas now are available for those who filed applications in the F4 visa category in May, 2004 or earlier. While that may appear to be a wait of about 13 years, in fact, since less than a year's backlog usually is resolved in a year, the wait may be 20 years or longer. Until a visa becomes available, the foreign national sibling would not be able to apply for adjustment of status (and apply to get an Employment Authorization Document - an "EAD" or "work permit"). As you can see, an application by a sibling rarely is a worthwhile immigration strategy, and so it usually is wise to explore other immigration possibilities. Other possibilities may be nonimmigrant (temporary) visas or immigrant (permanent) visas based upon employment. Some of these, such as applications for those with exceptional abilities in the sciences/engineering, can be self-petitioning, while others may require a qualified sponsoring employer. A significant part of our firm's practice is representing researchers, engineers, scientists, professors and similar experts in immigration applications specifically geared for such professionals.