The original question had to be edited. Brian's visit with his father is the result of the recent divorce between his parents. His mother initiated it. The courts ruled that Brian is to spend the summers with his father. This becomes the reason he is going to Canada to spend the summer with his father.
This is significant for a couple of reasons. The first is that the visit to his father sets the entire narrative in motion. Brian visits his father in the Cessna plane with the pilot who suffers a heart attack at the helm, forcing Brian to crash land the plane in the wilderness. The other reason that this is significant is that the time in which Brian starts his travel in the plane, it becomes evident that he is sorting through his emotions about the divorce. He feels estranged and alienated as a result. He knows about "the secret" that caused the divorce, while his father does not know. All Brian knows for certain is that he is to live the life of a split consciousness. It is interesting to note that at the end of the narrative, Brian's parents get back together, trying to make their relationship work. It does not succeed and they resume their divorced ways. Brian is able to conquer the wilderness, but not divorce.