I'm sorry to hear your brother is refusing his meds. Like up to 50 percent of the people diagnosed with SZ, he may have a symptom called anosognosia, which is the lack of awareness that he has an illness. I recommend you read Xavier Amador's book I Am Not Sick, I Don't Need Help, the current edition, which tells you how to couch what you say to a loved one to influence him to take meds and stay in treatment.
For now, I would make the case that he is a danger to himself or other people. I'm not sure if you would be comfortable saying he threatened you or a family member or someone else. It's sad when a person is unstable, that means he or she IS clearly a danger to themselves in that they can't care for themselves or carry out the basic functions of adult life.
About 19 years ago in New York City when I was in the halfway house, I knew a guy who was admitted to the residence because he was homeless and had a mental illness and had nowhere else to go. The problem is, most residences want their clients to be medication-compliant. I know of one mental health residence in New York City that possibly doesn't require its residents to be medication-compliant. I know that this residence is for people with substance abuse and alcohol problems, I could see for you if it accepts people who only have mental illnesses. It may, though, only take people living in NYC.
This is a tough one. I would suggest that if at all you don't feel comfortable, make the case that your brother is a danger to someone, and do what you have to do. Maybe the shelter staff could back you up on this claim.
It is sad, it is sad and scary, that the law protects people who are actively psychotic, who are the most vulnerable members of society. Because, chances are, he will be the victim of a crime, not the perpetrator.
I'm at a loss as to what I can say further except, maybe you want to claim he's a danger to you. Whatever you do, I suggest you read the Xavier Amador book.