Thank you for your question. I am sorry to hear about this situation.
In California, an individual has the right to refuse medical treatment as long as they are able to give consent. A doctor will not provide treatment to a patient unless that patient has given his/her informed consent. This is always the case unless the patient has reached an emergency situation, which is defined as a situation requiring immediate treatment of a medical condition that would otherwise lead to serious disability or death.
Accordingly, you are not able to force your husband to submit to medical treatment unless he consents to it, or unless he is in an emergency situation. As an RN who has worked in the ICU, you are aware of when his situation reaches an emergency level and can at that time take him to a doctor for treatment (it does not have to be in an emergency room or by way of an ambulance). I would suggest that if he has become psychotic because of his medical condition, then you can take him to the emergency room and get him admitted for treatment. In the end, the doctor who is going to provide the treatment will make an independent assessment of whether your husband has the mental capacity to consent to treatment that is needed. If he does not, and the treatment is needed to prevent death or disability, the doctor may then treat without your husbands consent (unless there is a living will or declaration wherein your husband has stated that he does not consent to treatment).
Unfortunately, your husband's rights to give his consent to medical treatment outweigh your and his doctor's best judgment as to treatment he may need.
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