Legal Question in International Law in California

Yes. There is a Hague Convention treaty governing international enforcement and collection of judgments. Whether it would be worth his time and expense to go that route is another question, but there is legal process for doing so. Effectively he gets the Italian court to issue a request to the courts of the U.S. to enforce the judgment under the treaty. He then files in the U.S. courts invoking the treaty and the request from the Italian court. Unless you can prove something that is so corrupt, illegal under Italy's own laws, or otherwise completely illegitimate under U.S. principals of rule of law is the only way the Italian judgment was obtained, the U.S. courts will then enter their own judgment on the terms of the Italian judgment, and allow him to apply U.S. enforcement of judgment processes to collect it.