When the brothers were reunited, Hans explained how it was that he was still alive. After having been wounded towards the end of the war, he had been sent to hospital and was separated from his unit. The hospital had been bombed(1) and Hans had made his way back into Western Germany on foot. Meanwhile, his unit was lost and all records of him had been destroyed. Hans returned to his family home, but the house had been bombed(2) and no one in the neighborhood knew what had become of the inhabitants. Assuming that his family had been killed during an air raid, Hans settled down in a village fifty miles away where he had remained ever since.
In the above paragraph, there are nine verbs in past perfect tense. I think I understand why past perfect is necessary for having been wounded, had been bombed(2), had become of, had been killed, and had remained. However, is past perfect necessary in had been sent, had been bombed(1), had made his way, had been destroyed? Can we use simple past instead?