An evaluation of mental capacity is critical to a clinician's judgment about whether or not persons can make medical treatment decisions on their own behalf, and uncertainty about their ability to meaningfully participate in that process is one of the more common reasons an ethics consult is requested. The care of decisionally incapable patients—particularly those who lack advance care documents and no living relative who can speak for them—presents a quandary to healthcare personnel attempting to plan care in their best interest, especially when options are multiple but none are ideal. These situations can be further complicated if involving a patient with a dual diagnosis of mental retardation and mental illness living in a community group home.I acknowledge the support of Mark G. Kuczewski, Professor of Medical Ethics and Director of the Neiswanger Institute for Bioethics & Health Policy Stritch School of Medicine, Loyola University of Chicago, for his guidance and support in the preparation of this manuscript.