What if he is an F-1 student?
You will need to submit your son's I-20 Certificate of Eligibility for Nonimmigrant Student Status.
I don't have a current DHS document for him. Is there anything else I can use?
Yes, other documents may be accepted, but they need to contain your son's name, his date of birth, and his biological parents' names. We also like it to have a recent photo, but we can accept it without a photo if it has enough information to verify his identity.