This is an excerpt from 'New Concept English 3 Lesson 36'
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 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 and no one in the neighbourhood 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.
My questions are
(1)What is the past for the past perfect in "The hospital had been bombed and Hans had made his way back into Western Germany on foot."
(2)Is there some extra grammar point I need to know about past perfect tense in a narrative besides "past perfect is past before the past" because the uses of tenses in this paragraph overall are very confusing to me.