My brother (69) is in rehab for diabetes, urinary infection and toxicity in his blood with delirium. Insurance will no longer pay. What now?

Also, possibility depression, signs of dementia plus bi-polar off & on. The insurances does not want to continue to pay. I have no power of attorney and he needs not to be on own, plus unsafe to return home alone without 24 hour supervision. I am waiting on expert witness information for guardianship but rehab needs to release him today. He wants to just be released and feels he's being held as a prisoner. I cannot do anything unless I get his permission. I was going to let him stay with me, & 1st said would go along with decision to not be left alone. But a family meeting totally disagreed, so advised best not to have him live with me. Today, is when insurance will not pay, so what will the nursing home rehab do with my brother now?