California law does not differentiate youth from adults in the naloxone training statute, and says nothing about parental consent. Therefore, any person can be trained. You can cite Cal Civil Code § 1714.22(f):

 

(f) Notwithstanding any other law, a person who possesses or distributes an opioid antagonist pursuant to a prescription or standing order shall not be subject to professional review, be liable in a civil action, or be subject to criminal prosecution for this possession or distribution. Notwithstanding any other law, a person not otherwise licensed to administer an opioid antagonist, but trained as required under paragraph (1) of subdivision (d), who acts with reasonable care in administering an opioid antagonist, in good faith and not for compensation, to a person who is experiencing or is suspected of experiencing an overdose shall not be subject to professional review, be liable in a civil action, or be subject to criminal prosecution for this administration.

or Medi-Cal providers:

 

California Code of Regulations, Title 22, Section 51473.2 
Under the Medi-Cal Minor Consent Program, providers may provide services to minors under the age of 21 without parental consent if the services are related to sexual assault, pregnancy and pregnancy-related services, family planning, sexually transmitted diseases, drug and alcohol abuse treatment and counseling, and outpatient mental health treatment and counseling.   - See more at: http://www.cfhc.org/advocacy/policy-priorities/confidentiality#sthash.SxP5cPzb.dpuf