GC Eligibility from brother?

[carsnoceans]

I am a US citizen and would like to apply for my brothers GC however there is a bit of technicality in my case.

We share the same parents however my brother was legally adopted at the age by my uncle at age of 3. So, legally speaking, he has a different last name than mine. However his birth certificate shows his real last name and natural parents (i.e. same as my parents). The last change can be explained by showing his legal adoption papers to my uncle but I am not sure if he is still eligible for GC sponsorship from me. We are biological brothers but I don't know about the legal view here. Am I eligible to sponsor his GC?

We are both over 25y.o. and he is on F1 visa currently (if it matters).

Thanks for the help!

[JoeF]

Even if it is possible, it would take 10-12 years. During that time, he would have to maintain legal status on his own, or leave the country. And on F1, it may be hard to travel abroad and come back once the immigrant petition is filed.

[carsnoceans]

Thanks Joe. I understand the possible constraints and long wait time but am I eligible to file for him, technically speaking?