Unmarried Sibling 25 yrs old living in Afghanistan. Can I sponsor him? Yes or No?

[JaySid]

I am a U.S citizen. I am sponsoring my parents from Afghanistan real soon. However, I have an unmarried brother 25 yrs of age also living with them.
What will happen to him? Conditions are bad in Afghanistan, and he has no other family out there. Can I sponsor him as well?
I'm confused reading all these age limit requirements in different forums.
PLZ HELP. I would really appreciate it.