CCC to UC Engineering transfers need to complete all the required major transfer classes (may vary depending on target UC campuses) along with the General Education requirements. The minimum transfer units required by time of matriculation (completion by spring semester/quarter prior to transfer) is 60 semester/90 quarter units.
Since he will be a Junior level transfer, his HS record will not be considered unless he has AP credit and Dual enrollment courses on his transcript. DE courses that are UC transferable will be part of his UC Transfer GPA.
Assist.org will help him figure out the requirements from his CCC to the UC target campuses. UC Transfer admission especially for UCB like all the UC”s will put priority on his UC transfer GPA, completion of the transfer requirements and PIQ’s. Having some major related EC’s can also help.
I have linked the UC Transfer GPA by major and UC campus. This data is from 2022 admits but 2023 admit data will be available in February. It shows the admitted UC Transfer GPA range, enrolled Transfer GPA range, admit rate for each major and yield. This will given him an idea of what GPA can be expected to be competitive as a Transfer.