I have a sister in the US and she will be a US Citizen soon. She is planning to file a petition for my parents so my parents can become legal residents of US as well. However, we have two siblings who are minor. One is 20 years old and the other is 18 years old. What is the probability that my siblings will be included in the petition that my sister will file for my parents? How long does it usually take before they can get their papers processed.Thank you.

According to the USCIS, your minor siblings cannot be derivatives under your parents petition because they have an independent (FB-4) petition that can be filed by their USC sister.

Your parents are immediate relatives, so there is no visa priority date wait, but the FB-4, brother or sister of a USC is backlogged about 10 years or more.

Please consult with an immigration attorney to confirm.