As used in the Probate Code [N.M. Stat. Ann. Chapter 45] the term “incapacitated person” means any person who demonstrates over time either partial or complete functional impairment by reason of mental illness, mental deficiency, physical illness or disability, chronic use of drugs, chronic intoxication or other cause, except minority, to the extent that he is unable to manage his personal care or he is unable to manage his property and financial affairs.