I'm very sorry to hear about your brother. This is really tragic. These disorder really waste lives. Your intuition about your brother's condition is probably more correct than not. Differentiating bipolar disorder from schizophrenia
can be difficult. When clinicians absolutely cannot decide because the person really does show the most prominent symptoms of both disorders, there is a disorder called Schizoaffective Disorder
. As a practical matter, if he shows psychotic symptoms e.g., most commonly delusions and hallucinations the antipsychotic medications used will be the same, regardless of the specific diagnosis.
Getting people such as your brother is usually difficult because they oppose it. As you note, they dislike the side effects of the medication, etc. The odds of getting him into treatment improve if the entirety of his social support network work together to push or shuttle him into treatment. This may mean having all family members increase their phone calls and interactions with him and consistently urge him to see his psychiatrist. A more formal form of this can occur, which I'm sure you are aware of (an Intervention or family confrontation session). Also, if he starts to have legal problems e.g., gets picked up because he is disturbing the peace due to his delusions, the family should use this opportunity to talk to the judge and/or prosecutor to court-order treatment for him.
In some larger communities there is something called mental health court, which is a fairly recent development designed to help people with legal problems (such as the one I mentioned, and who have a serious mental disorder) You can read about it if you Google the topic. So unfortunately you may have get the family together to create a bit of a social support crisis in his life (e.g., family pressures, family intervention) or wait for one to occur---which it almost certainly will sooner or later (arrest for some inappropriate, public behavior), and capitalize on such a crisis by trying to insert yourself into the legal process with the prosecutor or court. Also, if he experiences a serious psychotic episode and a family member has a reasonable belief that he may be a danger to himself or others, you can take steps to have him involuntarily hospitalized. You may want to talk to your local community mental health center staff, police department or hospital inpatient unit about what actions they take, what steps need to occur, etc. Nearly always, the person, when confronted with the choice of being involuntarily hospitalized versus signing themselves into the hospital, will choose the latter (if they are mentally capable of doing so).
I hope this gives you some useful leads. Let me know if I have failed to answer any aspect of your question.
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