Strange question

Hi,
Im not sure where to begin so i figured a forum might be the wisest choice. I am trying to help a friend do some research concerning a mix up that happened to him and his brother years ago. The info I have is that he and his twin brother were recieving benefits until the age of 18. after 18 the one brothers stopped but my friends continued. he didnt get the money and was not aware of the dilemma. My friend himself was sued for the money and ended up having his tax refunds taken for 5,000 dollars before his father actually ended up being found responsible and paying the money. I wondered if there was a possibility if my friend is owed any money back from the monies that were taken from him while he was not even responsible for paying in the first place. This is a tough one so if anyone has even the slightest idea please throw it to me. I really appreciate it,
Thanks,
m