To dream of being befriended by a child can be a complex event. If you know the child in waking and dreaming, this may reflect a wish-fulfillment or projection. If you do not know the child from your waking life, he or she may be a reflection of yourself at a particular time in your past. The main puzzle piece to discern is the nature of your activity and relationship with the child.
Parenting a child can also be a simple wish-fulfillment dream or something more complex. Parenting a child may be a way that your brain is working out some difficulty in your own relationship to your parents or another relationship of responsibility.
Parenting can also be a power projection dream. There may be a relationship in your life where you feel out of control and want to bring it back under control. Since most of us have felt our parents exert emotional power toward us at different times, we are now doing likewise in the dream relationship.
The converse of this is dreaming of yourself as the child while other figures from your life exert power in different areas. You may have dreamt that you were playing dress-up in the office and your co-workers were all regular adult figures. In waking, you may in fact experience them as more powerful than yourself or even excessively powerful.