You always have the right to submit an open records request for this information to both the law enforcement agency that arrested your son and the district attorney's office that is prosecuting. Now they may decide to withhold most of the information under the "law enforcement exception" but they also may decide to release it to you. Depends on the county or agency.
But the answer that you have no right to see this information is just wrong. At the very least, submit an open records request and see what they say. I've received full reports through this process so it's worked for me. If they give you any trouble, you might consult with an attorney who knows about open records, such as myself, or just wait until your son gets a criminal attorney.
You never have the right to see the evidence or the offense report. The attorney will see the evidence and offense report and can review the information with you. If you are not indigent, you must hire a lawyer to represent your child. If you are indigent, then the court will appoint a lawyer to represent your child.
You do not have a right to see the evidence on your child's case. Only the attorney of record will be given access to the police reports and other evidence that the Prosecution has. Depending on whether you hire an attorney for your child or the public defender is appointed, the attorney of record may choose to review the evidence with you, however if there are the names of victims in the report then their identifying information will be redacted.