You & your family are entitled to "his" income/benefits, not his mother and not his grandmother, no matter if it was the amount a single person gets or a married person. You should go to ss & report the fraud. If he goes with you, it will be best because he may have information that you do not. He will do best coming clean with them but, if he won't, you should. Otherwise, you won't get any of that money. Either way, you are not receiving anything. He could be in trouble for lying but, his mother and grandmother will also be for accepting money fraudulently. So, if your husband won't go in with you, go in yourself. Don't delay.
Certified Paralegal, with 25+ years' experience.