I just checked the UC Irvine TAG criteria and the minimum GPA is 3.4, so your brother met that. Essay would not be required. So, I don’t understand how he didn’t get into Irvine.
http://www.admissions.uci.edu/applicants/tag.html
I just helped a family friend with his transfer applications from community college. He did UC Davis TAG but also applied to Berkeley, UCLA and UCSD. He also had a 4.0, excellent EC’s and wrote good essays for the non-TAG schools. He was accepted at UCLA and UCSD. Choose UCSD, where he was offered a Regent’s scholarship.