Brussels-Iran has freed Belgian aid worker Olivier Vandecasteele after almost 15 months in custody, in a prisoner exchange facilitated by Oman, senior officials said Friday.  Belgium’s Prime Minister Alexander de Croo said the 42-year-old had arrived in Oman and added: “If all goes to plan, he’ll be with us this evening. Free at last!” Separately, Oman’s foreign ministry announced it had helped broker an “exchange deal” and that an Iranian previously held in Belgium was on his way to Tehran. “Olivier spent 455 days in prison in Tehran,” de Croo said. “For me, the choice has always been clear. Olivier’s life has always come first. It’s a responsibility that I take upon myself, that I accept. In Belgium, we do not abandon anyone.”