Your friend will not be punished for divorcing his wife. That said, divorcing her will very likely change his options for immigration. I would suggest he consult with an attorney to get a detailed view of his options.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It... more
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.
Your question is not clear.
1. If you already filed the petition and have the conditional green card and are ready to remove the conditions (the 2 years is expiring), you can still obtain residency if you prove you entered the marriage on a good faith basis. This is not easy. You need an attorney.
2. If you have not yet filed the marriage petition you can self petition under VAWA if you can prove you were a victim of domestic violence by your USC spouse. This is also not easy to do and you will need an attorney for this.