Unfortunately since a pre-trial is usually not a hearing it's a very informal setting.
Since you can't afford a private attorney, you are probably going to have to do the best you can with the public defender - one idea, be very nice to them - they have a high case load and actually do care, but they are regularly attacked by the judge the DA and their own clients.
Also, since it's your adult son, maybe he can afford an attorney, many take credit cards.
I agree with Mr. Williamson. Public Defenders are overworked, but highly qualified attorneys.
If you can't afford a lawyer, a public defender is better than going it alone.
The injustice with the private hearing seems to have been dealt with by taking a firm stand with the bailiff.
Edward J. Blum