Did the student graduate from high school in California after three years of attendance to qualify for AB540 rules?
If the parents move out of California before the student starts college at a UC, then a dependent-for-financial-aid-purposes student will lose California residency, but will have non-resident tuition waived and be eligible for in-state financial aid if the student meets the AB540 rules.
https://admission.universityofcalifornia.edu/tuition-financial-aid/tuition-cost-of-attendance/ab-540-nonresident-tuition-exemption.html
https://admission.universityofcalifornia.edu/tuition-financial-aid/types-of-aid/who-can-get-financial-aid/ca-dream-act.html
Example form from UCB (other campuses may have their own forms):
https://registrar.berkeley.edu/sites/default/files/pdf/UCTE_for_Elig_CA_HSGrads.pdf