老二应该就已经是CITIZEN.
Q: I was born overseas to an Australian parent. Am I eligible for Australian citizenship by descent?
Ans: You are eligible if you were born overseas on or after 26 January 1949 and meet the following requirements:
----one of your natural parents was an Australian citizen at the time of your birth
----you are of good character if you are over 16 at the time of application
----if your parent became an Australian citizen by descent, he or she must have been present in Australia for periods totalling two years at some time in their life.