Since you are online, visit
www.irs.gov. It is easy to figure out whether it is necessary for him to file a return. If he needs to file a return, instructions and forms may be accessed there. He may also be able to e-file for free! This is a government site and available to help anyone. I have used it to answer my tax questions and file my taxes for years.
Just visited this site-he may want to file this year even if he doesn't have to. You must file in order to get the 2007 tax rebates, even if you would not normally be required to file.