No, he's not obligated to report it. He can divorce her, but he will still be obligated under the Affidavit of Support until certain events happen. I suggest that he read this article on the subject:
There is no such "obligation" for a spurned USC to "report" any such thing. Even if a disgruntled USC sends a letter to USCIS stating the couple no longer lives together, it will pretty much be ignored.
Your son's estranged wife can still (and probably will) remove the "condition" on her temporary green card by filing fr and obtaining a divorce and then filing Form I-751 by invoking one of the many exceptions to the joint filing requirement.
Your son should divorce and move on and be more careful next time. Sorry, but that's the reality.
Behar Intl. Counsel 619.234.5962 Kindly be advised that the answer above is only general in nature cannot be construed as legal advice, given that not enough facts are known. It is your responsibility to retain a lawyer to analyze the facts specific to your particular situation in order to give you specific advice. Specific answers will require cognizance of all pertinent facts about your case. Any answers offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship.
He is not obligated to report his wife to USCIS. Nor should you. Your son might want to consult with an immigration attorney to better understand his options and the immigration consequences of divorce, not only for his wife but also for himself.
He has no such obligation. If he wants to file for divorce or wait, that is between him and his wife.
Heather L. Garvock Attorney Ellis Porter, PLC 2701 Troy Center Dr., 410 Troy, MI 48084 Phone: 248-519-9900 Fax: 248-519-9901 Email: firstname.lastname@example.org For more information about current issues and developments in immigration law, visit my blog: www.miimmigrationnews.com The information I provide on my blog and Avvo is for informational purposes only and does not constitute legal advice or create an attorney client relationship.