He needs to hire a lawyer now, not later. A court appointed attorney will mostly mean a ticket for deportation as they are not well-trained and they don't care because they work free for you. You need to chat with your local immigration attorneys and ask for recommendation for criminal defense lawyers who are familiar with immigration issues.
Look, please do not use 只是用手打两巴掌 to down play his action. What if I 只是用手打you 两巴掌?