Criminal Law Questions? Ask a Criminal Lawyer.
That is a decision left almost completely up to the judge, so it depends on that judge's particular views. That said, there are a few things you can do. First, your son needs to get into an AA class to show the judge he's taking his sobriety seriously. Second, the judge needs to know that he has support. You or other family or friends can write letters to the judge asking to keep him on work release. Other than that, it is completely up to the judge, but he does have the power to keep him out of jail.
Is there anything else I can help you with?