First, your boyfriend;s psychiatrist will report this to the police. That is what she means by reporting this.
Your boyfriend absolutely MUST NOT say anything further about this, to you, other family members, and ESPECIALLY THE POLICE. He needs to keep quiet about this
Second, your boyfriend needs to get in touch with a criminal defense attorney as soon as possible to discuss what should be done next. He needs counsel.
Nothing in this communication should be considered legal advice. Nor should this communication lead you to believe that an attorney-client relationship has been created. Only after thorough analysis of your case with you in my office can I provide effective legal advice on your specific issue.