Your freind can obtain a copy of his Social Security card through the Social Security office. The other information can likely be obtained from the original sources also. If the parents continue to block him he should seek an attorney which can seek to have him declared an emancipated minor and he can then sue for his records. The other method would likely result in less cost and turmoil.
If he would like to pursue emancipation, he should contact a licensed Georgia family lawyer to explore his options.