A self petitioning alien is not required to provide an affidavit of support. However, the alien must provide proof that he is going to continue in his field of endeavour and be able to sustain themselves from that endeavour. Thus, if your friend is an alien of extraordinary ability in athletics then he will need to provide evidence of how his skills will allow him to earn money to support himself.
Your friend needs to consult with an immigration lawyer in person or on the phone to assess the best options relating to the EB-1a Petition.
In order to answer this question, I would need to know answers to a number of questions including whether your friend applied through an employer or self-petition. Did your friend use a immigration lawyer to file his petition?
Generally, if your friend filed the EB-1 through an employer, then he would need an Employment Letter.
Please contact our law firm for a consultation to evaluate how move forward.
Good luck to your friend!
Nikiki T. Bogle, Esq.
BOS LEGAL, LLC
Phone: (800) 342-1733 ext. 101
Most employment based immigration do not require an affidavit of support (unless exceptions). Please talk to a good immigration lawyer that has handled EB1 cases for more information. Check the memo attached on affidavit of support from USCIS
Note: The above is provided for informational use only. One should not act or refrain to act based solely on the information provided. No attorney client relationship is created unless a retainer is signed by the attorney and the client.