W2 Forms as Only Evidence

I'm helping two brothers do their applications but, one of the brothers only has W2 forms as evidence for the years 2008-2012. He graduated from high school in 2008 and his W2 forms are the only evidence he has for those years. Would the W2 forms be enough or does he need more proof?

I'll say w2 forms are enough.

he doesnt have any bank statements?
any doctor letters?

He has a fishing license for the year 2009 and a gym membership for between 10/27/10 to 10/27/11. Other than that the W2 forms are all he has.

Don't forget he also needs to provide evidence from June 15, 2007 thru his graduation date. High school transcripts (official sealed) would help as well.