Documentation
You, as the sponsor, will need the following:
A completed I 130-1
A copy of your birth certificate and a copy of your siblings birth certificate.
Proof that you are a US citizen. This can include a valid passport or a copy of your birth certificate. Plus any other valid documentation if you were born outside of the United States.
If you and your sibling were adopted, are half siblings, or had step parents, it is still possible to gain entry to the United States. The documentation you will need could include:
Copies of any decrees stating when you and your sibling were adopted, before the age of 16.
Any documentation showing that the marriages of your natural parents and possibly step parents were legally terminated.
Evidence that you have the same father but different biological mothers.
Conclusion
This is only a sample of the very thorough documentation needed to make sure you and your siblings cases will be fairly treated under the US immigration system.
Please use Visa Emperor's expertise in guiding you through granting your sibling right of permanent entry into the United States.