It is illegal for an adult to to what this "boyfriend" is doing. Dating in and of itself is not illegal. Touching a minor , including kissing, for the purpose of sexual arousal is not legal. Suggest that parents call cops and speak with a civil attorney about the possibiity of a restraining order.
The above is not intended as legal advice. The response does not constitute the creation of an attorney client relationship as this forum does not provide for a confidential communication.
This person is playing with fire. Doing anything with a person under the age of 18 in california can get you in trouble - at the very least, the conduct may be considered "annoying" a minor, which is considered a sex offence in CA, and has dire consequences. If the "caressing" was contact with an intimate part (i.e. breast), even over clothes, then the consequences are even worse. That said, if you feel that a crime has been committed, call the police and let them investigate.
Mr. Feasel is a former Deputy DA in the SF Bay Area with over 10 years of criminal law experience. Nothing stated on this site shall in anyway be construed as legal advice, or as creating any attorney/client relationship. If you would like to hire Mr. Feasel to further investigate your situation, feel free to contact him thru this site.