I am a LPR and applied for my unmarried son when he was 18. His petition has now become current at 21. However, under CSPA he is ok as long as he adjusts status within 1 year. What does that mean? Must he file a 485 when he arrives in the US? or does it mean he must have his interview in the consulate within 1 year? Or is it something else I am missing? Any clarification would be helpful. Thanks.