The law provides in part that a minor’s “willful misconduct” causing injury or death to another, or damage to the property of another, “shall be imputed to the parent or guardian having custody and control of the minor” for civil liability purposes. (Civil Code §1714.1, et seq. as well as under the Education Code § 48904(a)) The law also provides for damages for mental distress caused by bullying.
Your school district may have additional policies. For example, the Los Angeles Unified School District has an Anti-bullying Policy, LAUSD Anti-Bullying Policy Page as well as children’s rights under Article 1, Section 28(c) of the California State Constitution and the relevant portions of the California Education Code 32270, et seq. which should be reviewed.