POA

The agent under a Medical Power of Attorney, not the agent under a Durable [Financial] Power of Attorney has the authority to admit the person granting the POA to a facility.  Facilities often ignore this either because they do not know the law or because they know the DPOA agent has access to funds to pay them.  Moreover, other than a guardian of the person, no one but your sister-in-law has the right to say where she lives.  She can leave at will. Her husband would have priority both in making medical decisions for her in the absence of a Medical Power of Attorney and in applying for guardianship.   Whether your sister-in-law can receive adequate hospice care at home is another question.  There are four levels of hospice.  Not every company provides all four.  Your brother might want to investigate this before arguing that she should be allowed to die at home.