In "A Boat to Nowhere", were Loc and Mai's parents killed in the war?(yes or no)
Yes, Loc and Mai's parents were killed in the war, or, to be more specific, their deaths were the direct result of conditions created by the war.
Although their deaths were not combat-related, "Grandfather said that the war had killed both Father and Mama". Previously, the family had lived in the city where Father was a doctor, in "a big home with flowers in the garden". Then, with the advent of the war, Father "had to go away to be a doctor to the soldiers", and he never returned. A short time later, Mama went to the hospital when Loc was born; she never came back from the hospital. Grandfather took young Mai and the infant Loc away from the city in a harrowing flight, wandering from town to town until they were taken in at the tiny village where they reside at the beginning of the story (Chapter 2).