How can my partner get citizenship even though he is already here?

My boyfriend is Chilean and I am American and we want to be together. He came to the US when he was little with his parents so he became an automatic citizen, but then he found out that the government had screwed up his social and now he isn't a citizen. The problem is this happens all the time so the government obviously wont admit their mistake, He is 25 so he is too old to change it. His license expires next year which will mean he wont be able to drive or get a job...is there anything we can do? Any possibility? I know marriage doesnt work because marriage is at a federal level which gay marriage is not recognized. Please help me! I love him so much and i dont want to lose him! Maybe a dual citizenship???Anyone?