My son lived with me until late July (he was a college student). At the point he moved out and got his own place. He got married in September. I'm answering the questions in order did he get married, and then will he file a return, and then it asked "Did [your son] file this return just to get a refund of withheld tax?" That question doesn't make sense. He's filing taxes because it's required by law. Of course, he's hoping to get a tax refund, but that's not what the question asks. So how do I answer this?
Not everyone is required to file an income tax return each year. Generally, if your total income for the year doesn't exceed certain thresholds, then you don't need to file a federal tax return.
TurboTax is asking if you son was not required to file but he had some taxes withheld so he is filing to get a refund. Please check the link for Income thresholds and for information on who needs to file.