If you have his/her social security number it would be easy to search death rolls at www.ancestery.com you can get a free month to search for him. This will help you know if he's alive or dead.
1 Additional Answer
You can find out if someone is still alive by calling up the local health department or title office where they reside and asking if they have a death certificate for the person you are looking for. Birth and death records are public knowledge.