The boat might symbolise an aspect of his journey through life. In order to grow, he needs to change his relationship with his mother. Death usually symbolises change. Perhaps his unconscious, in its infinite wisdom, understands that he is too dependent somehow on his relationship* with his mother.
Carl Jung, for all his faults, believed that the characters in our dreams are merely symbols of our unconscious desires. By questioning what individual elements, like the boat and the mother figure, represent to your son’s conscious mind, so he will begin to understand how his unconscious mind (the dream) is processing his experience and emotional development.
*I say relationship because the character in the dream may not necessarily represent the child’s mother, but rather a collection of beliefs that combine to become ‘mother’ in his interaction with the world.
Jung believed that the influence of the mother on a child derived not only from the actual mother, but also from the Great Mother archetype, a universal image or symbol, along with influences from the child’s own psyche. The child’s idea of “mother” may or may not correspond accurately to the actual mother, then, depending on the child’s own temperament and personality combined with universally-held archetypes and the influence of the actual mother.
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