At the age of eleven, he entered the seminary of Saint Anne in Jerusalem, which is run by the White Fathers.
After World War I, Coueter continued his education in Damascus and studied philosophy and theology.
First, he established a Melkite parish in the Roman Catholic Archdiocese of São Sebastião do Rio de Janeiro and received approval in a Roman Catholic church in Rio de Janeiro worship to celebrate in the Byzantine Rite.
The Archbishop Jaime de Barros Camara of Rio de Janeiro (1943-1971) appointed him in 1951 with the approval of the Holy See and the Melkite Patriarch of Antioch Maximos IV Sayegh Vicar General and entrusted him with the responsibility for all Melkite Christians in Brazil.
Pope Paul VI by decree of 1972 gave the Melkite Greek Catholic Church its own bishopric in Brazil.