my minor son was denied his i 485 because he left the country without advance paole should i just reapply or appeal the denieal

I do not see a basis for appeal and it is clear that leaving the country without advance parole during the time that an I-485 application to adjust status is pending invalidates the application. I suggest reapplication (if possible) for him although there may be problems arising from his present status. You may ultimately have to consider having your son do a follow to join immigrant visa application at the American consulate or embassy in your home country if he is no longer eligible for adjustment. You may wish to consult an immigration lawyer before taking further steps.  Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.