I filed !-130 petitions for my Wife and Stepson which was approved. I received immigration packets for both of them. On DS-230 Part I item 15 for my stepson it asks for fathers name etc. My stepson has lived with my wife and I for over 10 years. The biological father is unknown and the preference category is (IR2-PHIL).
DO I PUT MY INFORMATION ?

My stepson also received an I-864W (Intending Immigrant's Affidavit of Supporting Excemtion). On Part 2 REASON FOR EXEMPTION there are four boxes with the second box stating "I'm under 18, unmarried and immigrating as the child of a U.S. citizen etc ....
IS MY STEPSON CONSIDERED THE CHILD OF A U.S CITIZEN FOR PURPOSES OF THIS AFFIDAVIT?

Also, my stepson being 14 years old ...
WHO WOULD SIGN THIS DOCUMENT AND THE "NOTIFICATION of APPLICANT READINESS?

Thank you for any help I receive