If you apply today, he will not get his greencard until at least 2020. I know this because I am in the same boat. My brother applied for mine back in 2007 and I still have not received it. Lawyers say it takes around 10 years. The priority date for sibling category is currently 2003. Meaning right now they are processing applications filed back in 2003.

Search for "immigration lawer" in google and email them. Some may provide free email advice to a few questions.