By Michael Schwartz and Holly Yan
JERUSALEM (CNN) -- Former Israeli Prime Minister Ariel Sharon's health will continue to deteriorate, a hospital director said Monday.
Doctors are unable to stabilize Sharon's renal functions and other vital systems, said Zeev Rotstein, director of Sheba Medical Center in Tel Hashomer, Israel.
Rotstein added that the danger to Sharon's life "has grown."
The 85-year-old has been in a coma for eight years and is suffering from multiple organ failure. News broke Wednesday that his health had recently worsened.
Sharon is known as a highly decorated -- if controversial -- Israeli military figure who became prime minister in 2001. He slipped into a coma in 2006, when he suffered a major stroke that led doctors to put him under anesthesia and on a respirator. His term as prime minister came to an end.
Rising through military ranks
Born in 1928 in Kfar Malal -- a community that would later become part of Israel -- Sharon graduated from high school in 1945 and began working with the Haganah, a militant group advocating for Israel's independence.
He began his rise through the Israeli military ranks in 1953. Sharon helped establish an elite commando unit and was eventually promoted to be an army major general. He held this rank during 1967's Six-Day War, which ended with Israel controversially expanding its territory.
Sharon went on to play major roles in subsequent Israeli military conflicts as well, including as head of the army's Armored Reserve Division during the 1973 Yom Kippur War.
He then began segueing into government, including stints as Prime Minister Yitzhak Rabin's military adviser, agriculture minister and defense minister from 1981 to 1983.
Invasion of Lebanon
Sharon also orchestrated Israel's invasion of Lebanon, an effort aimed at Palestine Liberation Organization (PLO) fighters that also left hundreds of Lebanese civilians dead. His actions led many in the Arab world to call him the "Butcher of Beirut."
An official Israeli inquiry found Sharon indirectly responsible for the September 1982 killings of as many as 2,000 Palestinians at the Sabra and Shatila refugee camps outside of Beirut, Lebanon.
The report -- which led to Sharon's prompt resignation -- determined the then-defense minister did nothing to stop Christian militiamen allied with Israel from entering the camps, despite fears they might seek to avenge the killing of their leader the previous day.
Sharon did not stay out of the spotlight for long. His adviser Ranaan Gissin said Sharon "felt betrayed by his government." Sharon also sued Time for a magazine article implying that he had foreknowledge and a greater role in this massacre, with a jury later finding the U.S.-based publisher guilty of defamation but not of malice.
Becoming prime minister
Sharon went on to hold a several other Cabinet posts from 1984 to 2001, when he won a special election to become prime minister.
By then, as head of the Likud party, Sharon was considered a hawk. And early on, he took the offensive by sending tanks and troops into Palestinian territory and ordering the assassination of militant leaders.
But Sharon also took steps toward peace, such as agreeing with the late PLO leader Yasser Arafat on a timeline to halt Israeli-Palestinian violence and resume peace talks. But that effort was undermined by Sharon's own party, which backed a resolution to never allow the creation of a Palestinian state.
Sharon later participated in talks with regional and world powers to discuss a "road map" for Middle East peace.
Immediately after he fell ill in early 2006, his power was transferred to Vice Premier Ehud Olmert. Surgeons removed 20 inches of his intestine the following month and, that April, Israel's Cabinet formally ended his run as prime minister after declaring him permanently incapacitated.
The former prime minister's health has fluctuated during the time he has been in the coma. In January 2013, doctors said testing on Sharon indicated some brain activity when he was shown photos of his home and heard his son's voice.
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