If he is incarcerated your chances are very slim of getting money, unless you are aware of any assets he may have. Your judgments is good for 10 years. However, your best bet is to contact a local attorney that specializes in collections, they have the ability to do skip traces.
I have often said you can wallpaper your entire home with the court judgments that can't be collected. It doesn't matter one whit where the person lives or is incarcerated. When you have a court judgment, you have the right to seize any property s/he owns that isn't protected by state laws called exemptions. If the property isn't in the same state where the judgment was granted, the judgment will have to be registered where the property is located before you can have local law enforcement take it. Hope this perspective helps!