One of student’s eligibilities for federal and state financial aid is that student has to be either a U.S. citizen or eligible noncitizen like a green card holder. There more categories about noncitizen who can apply for financial aid.
You must be one of the following to receive federal student aid: • U.S. citizen • U.S. national (includes natives of American Samoa or Swain’s Island) • U.S. permanent resident who has an I-151, I-551, or I-551C (Permanent Resident Card)
If you’re not in one of these categories, you must be an eligible noncitizen, and you must have an Arrival-Departure Record (I-94) from U.S. Citizenship and Immigration Services (USCIS) showing one of the following designations: • "Refugee" • "Asylum Granted" • "Cuban-Haitian Entrant, Status Pending" • "Conditional Entrant" (valid only if issued before April 1, 1980) • Victims of human trafficking, T-visa (T-2, T-3, or T-4, etc.) holder • "Parolee" (You must be paroled into the United States for at least one year and you must be able to provide evidence from the USCIS that you are in the United States for other than a temporary purpose and that you intend to become a U.S. citizen or permanent resident.)
If you have only a Notice of Approval to Apply for Permanent Residence (I-171 or I-464), you aren’t eligible for federal student aid.
I believe that I-485 is to apply to adjust your status to that of a permanent resident of the United States. You said that you and your family have been approved for I-485. If your family received social security numbers and Alien Registration numbers by approval of I-485, your son can apply for financial aid now. Your son can apply for financial aid at www.fafsa.ed.gov.