While it has been a few years since I have handled these kinds of situations, in order to obtain involuntary treatment, your family member needs to be evaluated by a doctor or ordered to treatment by a court. If you need to call the police about the acute behavior of your family member, you should advise them of the psychiatric issues and request that they take your family member to a hospital emergency room for evaluation. Sometimes taking out a restraining order on your family member is necessary. If the restraining order is violated, the police can arrest your family member and bring him in for evaluation or to court where the judge may order an evaluation. You might also consult with the local psychiatric emergency services team about stratagies for intervention. Alternatively, if your family member would agree to see your family doctor, a trusted friend or relative or a trusted pastor or priest, one of those people may be able to convince him to get some help. Also, you and the other family members might benefit from meeting with a therapist to help you deal with and strategize about how to deal with the situation. Good luck!
Gary S. Sinclair is an attorney licensed to practice in Massachusetts. If you wish to contact me or any other attorney on AVVO, just click on the attorney's name and you will find contact information. All of my answers are based on Massachusetts law or a simple reading of the law in your jurisdiction. All answers are for educational purposes and no attorney-client relationship is formed by providing an answer to your question. The information provided should NOT be relied upon for making legal decisions. You will be best served by hiring an attorney in your area who specializes in the field of law pertinent to your question.
Involuntary commitment is very difficult if your relative has not done something to indicate he is a danger to others or admit that he is a danger to himself. However, since he may be facing incarceration next week, he may be more willing to voluntarily commit himself if he sees it as away of escaping (temporarily) jail or mitigating sentencing.
If he has an attorney you should talk to him about getting help for your relative. You may also want to speak to the court clinician. Since his attorney and the clinician may have confidentiality issues you might also benefit from conferring with your own criminal attorney.
This is not legal advice and is not intended to create an attorney-client relationship. You should speak to an attorney for further information.