This dream is about a sudden storm (lightning, thunder, darkness – challenging and difficult circumstances in a person or a group of people’s lives caused by evil). One variation of water in dreams in visions is that it sometimes symbolizes overwhelming and difficult circumstances in a person’s life. It is as if the difficult circumstances want to overwhelm and destroy people.
This woman saw you and it symbolizes that you will be able to help her fend off this attack or be able to help her deal with these circumstances effectively. Your calmness helped her to stand strong as the dream showed how she changed the dirty (chaotic spiritual condition) overwhelming water into light blue (white mixed with blue gives light blue. Which means victory, holiness, purity, and righteousness mixed with the revelation knowledge of God) calm water. Because of her taking a strong stand in prayer and because she took authority over the situation the storm could not overwhelm and destroy her in a spiritual sense. She actually calmed the storm but only after you brought peace and calm into her spirit.
I do not know what caused the spiritual storm but I will tell you what the other symbols represent: a Boy symbolizes either a real person (her son) or a young ministry (her spiritual ministry) or a young relationship that she shares with a group of people. I personally think it is one of the latter two. 4 years old probably represents the age of the ministry or the relationship of the group of people or the characteristics of this group which is all about “revelation knowledge” (teachings, training, Bible school or something similar). The storm washed the shoes of the boy away which means the difficult circumstances either caused the group of people to lose interest in walking their faith-walk with Christ-like they should (if it is spiritual) or the group of people lost their desire to walk the path of life with each other (if the meaning is natural). See the meaning of shoes.
Mangoes symbolizes the fruits of the Spirit. The fruit of the Spirit is all about the characteristics of God (But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness, gentleness, and self-control). So this group of people or ministry craved for the fruit of the Spirit because it probably experienced a situation where there is a lack of the fruit of the Spirit. It appears that some people did not want this lady and her ministry to obtain the fruit of the Spirit by or from or through a specific person (tree). So they did not approve of a specific person. Because your friend ignored their wishes all “hell” broke loose. She will be or was probably persecuted because of her decision. I think your friend made the right decision or she will make the right decision but she must be prepared for whatever storm that decision will cause. The wonderful thing is that she will be victorious at the end of all this. All the young children that were overwhelmed and washed away represent young people (not spiritually mature) within this group who will be traumatized and disillusioned by this whole event. So they will be traumatized but it is not your friend’s fault and God will look after them.
So yes, your friend is facing a difficult time or she has already faced it or she is facing it right now. It will be very difficult for her and for other people but God wants to confirm that in the end, she will be OK. She will survive this ordeal and she will be victorious.
So what is this dream all about? It depends on what she pondered on or what happened before she had this dream. If the dream was direct from God then this is a warning to be ready for the coming storm in a spiritual sense.