The river represents the death of a loved one because the father randomly decides to leave and is never seen again. He was always fascinated by rivers, and even at one point wanted to be a crocodile in the river. The son had came back home to his father tilting his hat and leaving again. I think it can symbolize the death or mystery behind never seeing his father again, because the mother was in denial that this was even happening, and the son stayed there until he was old and gray, waiting for his father to return. He finally calls out to his father and sees him, then runs away afraid he will spend the rest of his life in a canoe. Perhaps he just sees what will happen to him if he goes out there.