US citizens who are at least 21 years old can petition their brothers and sisters for the green card. The siblings would fall under the F4 (Family Fourth Preference) category. The F4 category is the most backlogged of all immigration categories.
The process would begin with the US citizen filing an I-130 petition.The filing date of the I-130, as reflected on the USCIS receipt, is the priority date that will govern when a visa becomes available.
The sibling being petitioned will need to remain outside the US while waiting for the priority date to become current.
Once the priority date becomes current, and all of the final paperwork is done and fees paid, the sibling and their family, including children under 21 years old, would apply for immigrant visas at the US Embassy or Consulate. Upon arrival in the US, they would be processed for the Green Card.
Because the waiting times in this category will be more than ten years, it would be advisable to consult with an immigration attorney to see if the siblings have other options available to immigrate. Our Los Angeles immigration lawyers are available to assist you.