Did they change the settings to allow for global mode and to allow roaming?
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
I'm sorry to hear your son is having issues with his service abroad, JG7283. I know how important it is to have service when you travel to stay in touch with your loved ones. Let's look into this further and see what is causing this problem. What is the make & model of his device?