The 77-year-old music icon has claimed in new legal documents that her 47-year-old son is unable to care for himself due to his drug addiction.?According to People, Cher believes her son is "substantially unable to manage his own financial resources" and therefore needs a conservator to look after his estate. "Cher is concerned that any funds distributed to Elijah will immediately be spent on drugs, leaving Elijah with no assets to provide for himself and putting Elijah's life at risk." The Believe singer also argued that Elijah's estranged wife, Marieangela King, should not be his conservator because…