I have received letter(June 17,2019) for immigrant visa under F4 applied by my sister. At the time of application (priority date was October 2,2006 and approval date is July 22, 2009), my son was 13.eventually he's now aged out.I emailed to NVC to include him in the visa application process but they told under CSPA he's aged out and the US Embassy my decide for his visa. In that case, should I appreach the Embassy with him at the time of our interview ( myself and my spouse) with his all documents like passport, Birth certicate? My son will turn 26 on this November 2019 and is unmarried. A valuable suggestion/ advice would much be appreciated.