You can't get a healthcare power of attorney from someone who is mentally incompetent (severe dementia) and is unable to respond: only mentally competent, responsive people can issue powers of attorney, including health care powers of attorney.Her family will have to petition the court to appoint one of them (e.g. the son) as her legal guardian or conservator (either term may be used): that is the only way to get the legal authority they need. Your client may wish to contact NC Adult Protective Services: they may be able to provide help or at least guidance in applying for guardianship: https://www.ncdhhs.gov/assistance/adult-services/adult-protective-services