Although I am not licensed in your state, I expect any respondent will have a hard time answering your question directly. What can be said with confidence is that whatever the consequence may be, it will be much improved if he has a qualified attorney experienced in handling matters such as this at his side. I strongly recommend that you secure such an attorney for him. I'm sure one or more of the talented attorneys from MS will respond here. Reach out and talk privately with them so you can help him set a good course. Good luck.
I assume your stepson is a minor, under 18 years old. I further assume the case will be handled in the juvenile court in your jurisdiction. I further assume he has no prior criminal record. If so, he would be well advised to hire a criminal defense attorney in your area to represent him. There should be alternatives to a conviction (informal adjustment, volunteer hours, diversion, etc.) to resolve the case. Get counsel.
I am trying to give you a general answer to your question. We do not have an attorney-client relationship by this response on the avvo website. I have not been retained to represent you. I am licensed to practice law in Kentucky and in federal court in this state and the Southern District of Indiana. You need to seek legal advice from an attorney licensed to practice in your area..
You need to hire an attorney to act on his behalf. There are a multitude of questions that cannot nor should be answered on a public site. These are detail questions that could be raised for his defense. Also there are school matters that must be addressed as well I assume