Sue, it makes a difference whether he is in a county jail or in a state-run prison. If he is in a county jail, their mental health systems are hit or miss and can range from good to atrocious to non-existant. Not much you can really do there until he is released and then you can try through the court system for some type of legal guardianship to force treatment for him.
If he is in a state-run prison, it is a little different. The prison where I work has a mental health team headed by a Psychological Examiner, sort of a coordinator. He is the one who refers inmates for treatment to a psychiatrist who comes two or three times a week to see patients. The job titles may be a little different in Florida, but this is the person you should contact if you are concerned about his condition. He should also have a counselor assigned to him. They may be able to help and you could also contact this person to voice your concerns. But most prison counselors have huge caseloads and they are NOT trained mental health specialists. They help with problems with their jobs or if their laundry is lost.
The problem is that once he is released, their hands are tied and the prison staff can do nothing more for him. Released inmates are on their own as far as getting treatment and medications, if they are on them. If he is being paroled, they may insist on mental health treatment as a condition of his parole but it's very difficult, if not impossible, for them to enforce. If he is completing his sentence, "flattening", they can do pretty much NOTHING. If you want to try for some type of legal guardianship once he's released, and if the prison mental health staff agrees with you that he could be a danger to himself or someone else when he is released, they may agree to write you a letter to that effect that could help you if you go to court. It's a very difficult situation.