Hello jane cooke,
First of all, your son shouldn't be in prison. That goes without saying, although too often jails are the psych wards in America.
In the United States, it's all too common for people with schizophrenia to wind up in jails instead of hsopitals. Brooklyn, New York City, though, has a mental health court specifically for people with mental illnesses who have committed crimes.
Check to see if there is a mental health court in your city. Pete Early wrote the book, Crazy, about what happened after his son was turned away from a hospital: within 48 hours, the son committed a crime. Unfortunately, unless someone is deemed a danger to himself or others, no hospital will admit him. Dropping the charges I understand. I don't understand how the charges could be pursued if you dropped them, after all, he robbed you, not another person, so how could someone else override the charges?
What has his attorney or legal aid attorney if one was available suggested about bringing up his mental illness at the trial? You have to make it clear that you fear for your life after what happened, and that your son needs to be in a hospital. You need to exaggerate this to get him the help he needs, otherwise, if he's masking his symptoms or lying about them, people might just dismiss your claim or not think he needs help.
You say he is hearing voices telling him to harm himself. At that point, as you well know, he needs medication. Has he not been prescribed medication, or is he not taking his meds? I suggest you call the National Alliance on Mental Illness (NAMI) at their not line, (800) 950-NAMI (6264) to find out resources in your city, town or area that people in your situation have used to get their loved ones in treatment instead of jail.
I wish that your son gets treated soon for his illness. I want that it works out for you and him.
Regards,
cb