Only U.S. citizens aged 21 or older can sponsor a brother or sister for a green card.

 You’ll need to file Form I-130, Petition for Alien Relative, to begin the sponsorship process.

Sibling green card cases fall under the F4 visa category, which often takes 10–15+ years, depending on the country.

 You’ll need to show you can financially support your sibling using Form I-864.