If you are a United States citizen and at least 21 years old, you may bring your brother or sister to live and work in the USA as permanent resident (green card holder). Once your case for a brother or sister is approved, your relative must wait until a visa number can be obtained before they may travel to the U.S.
When your relative reaches the “front of the line," the U.S. Department of State contacts him and invites him to apply for an immigrant visa. This method is called “Consular Processing." After your sibling submits his application for an immigrant visa, the consular office will schedule him for an interview. Consular Processing may take several months, and your relative will not receive his visa until all the steps are completed. Once your sibling receives her visa, she may travel to the U.S. Your sibling will receive her green card soon after arriving.
If your relative is within the U.S. when his visa number becomes available, he can adjust his status in the U.S. It might take several months for the relative to receive his or her green card after applying for an adjustment of status, and he cannot leave the United States while the application is pending.
Only 65,000 visas may be issued to brothers and sisters of U.S. citizens per year. Due to the numerical cap, there are long waiting periods to obtain a visa in this family immigration category.
China, India, the Philippines, and Mexico are countries with a high demand for U.S. immigrant visas. Because U.S. law limits the amount of immigrant visas available based on country, your brother or sister will need to wait longer if they are from those countries. Waiting times for siblings from China and India could be 10 years or more. Waiting times for those from Mexico and the Philippines are often much longer.
Your brother or sister’s place in line will be based on the date you file your petition. Therefore, you need to file your green card application as soon as possible. Mistakes in the sponsorship petition can delay your sibling's case for months or years, so you should consult with an immigration attorney.