Legal Question in Family Law in California

You can only anull a marriage that was totally invalid. Otherwise you must get a divorce.

The fact that someone was not a resident alien at the time that you married them, is not a ground for nullity of marriage. It appears that you are thinking that you can annul the marriage for fraud, but that would be fraud perpetrated on the spouse, and not on the Department of Homeland Security. Further, the fraud would have to go to the heart of the marriage, such as procreative ability of the spouse, and not whether the marriage was going to last once he obtained resident alien status. As to whether this would affect his status as a resident alien, you would need to repost that question in the Immigration category.