United Arab Emirates President Sheikh Mohammed bin Zayed Al Nahyan has appointed his eldest son Sheikh Khaled as crown prince of Abu Dhabi, the oil-rich capital of the Gulf state, and named his brothers to top roles, state media said on Wednesday. Sheikh Mohammed, who became president and Abu Dhabi ruler last year after running the U.S.-allied OPEC oil producer for years, named his brother Sheikh Mansour as UAE vice president, alongside Dubai ruler Sheikh Mohammed bin Rashid Al Maktoum.