Hello all. My brother is married to a us citizen and got his green card through marriage. He has been permanent GC holder since May 2007. He is confused about when he can apply for citizenship. Is it 3 years or 5years. Also if he applies as married to a us citizen will the wife also have to go to the interview? She works for oxfam and is always out on humanitarian trips around the world. Sorry if i am asking too many questions together on his behalf but any help would be appreciated.