The Israeli hospital treating Ariel Sharon says the former prime minister has deteriorated further and he is now in `grave' condition.Sharon, who has been comatose since suffering a stroke eight years ago, suffered a downturn in his health last week with a decline in key bodily organs.The Sheba Medical Center said Thursday his condition has worsened and his family is by his bedside.Sharon, one of Israel's most controversial and iconic figures, suffered the stroke at the height of his political power as he appeared to be cruising toward re-election.