He doesn't need to become a US citizen. He is enjoying retirement since he was 70 years old. He lives here in Florida too. The only reason for him to become a US citizen is because he just want it. Yesterday after he failed his exam, he told me is not the end of the world, he is not obsessed to become one either, and after you guys clarify me many things. It's up to him if he wants to try it or not. :), but know him very well, I don't think he wants to do it right away, at least not for now.