One of the reasons that made Antonio leave Lubango, was the worsening of the political situation in the south of Angola as a consequence of the Berlin Conference in 1885. At this conference some European nations, mainly Germany, England, France and Belgium rearranged the countries of Africa in the way we know them today.
Germany occupied South West Africa, now Namibia, an arid and almost sterile country dominated by the Kalahari desert. The Germans looked at Angola, with its numerous rivers and rich farmland and decided to invade the south of Angola just before declaring war on Portugal in 1914 as a result of the Great War.
The Portuguese under the command of General Pereira de Eça defeated the Germans in Naulila* and drove them south of the Cunene river, which is now the border between Angola and Namibia. Before and after Naulila the Germans infiltrated agents into the south of Angola to agitate the native Angolans against the Portuguese.
The Cuanhama nation rebelled against the Portuguese, but in 1915 was defeated in Mongua by Pereira de Eça. The Cuanhamas, a nation of warriors constantly challenged the colonial rulers and it was not until they were defeated in Mongua that peace returned to the south.
This state of affairs was most likely the main reason why Antonio decided to leave Lubango, all his family and friends to try his luck elsewhere.
* Note - Further investigation about the colonization of the south of Angola (re. Fernando Cerviño Padrão) showed that Pereira de Eça never fought the Germans. Boer forces commanded by general Botha defeated the Germans in the South West Africa. After their defeat the Germans left Angola without a fight. In Naulila the Portuguese forces suffered a humiliating defeat.
The savanna in the south of Angola. The black dots are Wildbeast-Gnus
Loengue River in the Southeast of Angola