It's possible if a person went to community college for two years and then a state school for two years and lived at home for the four years. Plus, like someone said above, this article says that the student didn't accept loans. He may have gotten other assistance that didn't have to be repaid.
Cal State U schools are quite cheap on a per-unit basis compared to other universities (even in Cal). Most are 'commuter' schools with few students living on campus.
I'd guess he did exactly what you outline--community college, then state u, stay at home for all 4 years.