i have a U 1 visa. my wife and son were aproved to apply for a visa in 2010. my wife applied and has come to usa. my son was in college ,so he didnt apply in 2010. now he has finished college and would like to apply for the visa. but he is 23 yrs old now. he was less than 21 yrs when he was aproved for visa in 2010. the notice states "aproval U3. valid from april 23 2010- april 22, 2014. can he stil spply for visa?