My husband has lived in the US for about 28 years. His family filed when he was about 10 years old but only his mother and brother were called. As he was a child shouldn't he automatically become a citizen when his parent did??? Or does he now have to go through the whole process?
I believe he has to go through the process himself. I would check with the INS if I were you.
A child can only get derivative citizenship if both parents choose to be naturalized. Other than that, you have to wait until you are 18 to apply in your own right.
If you think he does have a claim to US citizenship, he can file for a certificate of citizenship - I think it is form N-600 but not sure.