Please give this interpretation to your friend.
Let us just look at the meanings of the symbols in the dream:
A city: A city is a symbol of security and safety. It speaks of safety and it speaks of permanency. Such is the city of God which is, in fact, the church of Christ. People find shelter, refuge, deliverance, and safety in the church.
In the dream, however, this city is a safe refuge for bad people and even evil forces, or so they thought. This city was a stronghold for evil.
The color red most often symbolizes a person who has an attitude of conflict, anger, vengeance, hate, and fury. There are a few exceptions as prescribed below but as I said, most of the time the color red symbolizes conflict, hate, anger, disunity, fury, hate, and vengeance.
Clay is a symbol of the frailty of human flesh. It speaks of the weaknesses of mankind. It also speaks of the fleshly nature of mankind. God changed all that when we were born of the Holy Spirit through Christ. But, we still need to crucify the flesh through obedience and through the pursuit of holiness. For instance, a person with a mustache of clay symbolizes a person who speaks fleshly words. So the city was built with a substance that is not strong but frail (human power).
The high walls speak of the difficulty to overcome the city. It also speaks of secrecy as things in the city are not clearly observed from the outside.
Circle around the city: A circle in a dream or a vision symbolizes unity. So the evil people and evil forces in the city are in unity. They stand together.
Your son walking away speaks of the right action that was required (as we notice in the rest of the dream). The people and evil forces in the city were hostile and a danger to your son. The right thing was to move away.
After this right decision, he suddenly experienced and observed good things: the green grass and hills which speaks of peace and prosperity (green grass and field) and authority (hill).
The calm (peace) and clear and blue lake: A dam or lake speaks of vast amounts of financial resources or spiritual resources kept in reserve for either an individual, a group of people like a town or city, or any other community or group of people or for people living in a specific area. These resources are available when needed. The color of the water and the condition of the water will provide additional information and detail regarding these resources.
The blue water speaks of the inspiration of the Holy Spirit (revelation knowledge).
The dirt road speaks of the city or the people and evil forces in the city offering access to the city. The dirt road, however, speaks of this road leading to fleshly desires, things, and a lifestyle (like the clay revealed as well).
The trees on top of the hill speak of prominent people who are steadfast and in order (straight line).
The wooden cabin next to a lake with calm blue and clear waters speaks of wisdom. It speaks of a person (represented by the cabin) making his home next to such a peaceful place. This speaks of spiritual and financial blessings because of this correct and wise decision (it is like the Biblical wise person who is like a willow tree planted on the banks of a river where it prospers and grows) (such a person is near God and purposely making God his source and “hiding place”. God is his strength.
Every time that your son felt happy in the dream speaks of the wonderful rewards when we act correctly and taking the right decisions.
The trojan horse speaks of the ignorance of evil people and evil forces in the city. They think they are safe but what they don’t know is that God cannot be ignored. God is invisible but He can become visible suddenly (in the sense of the destruction and havoc that He causes in the lives of evil people and evil forces) when a time of judgment and punishment comes. This is when He suddenly appears and swiftly acts.
A horse speaks of a person’s strength and power. It speaks of a person’s ability (means) to achieve something. It has the same meaning as motorcars (a ministry, motivation, or work situation of people). A person with a big, strong, white, powerful (engine capacity) motor vehicle speaks of a person with a good and powerful ministry or motivation in life. A person with an old rusted small motor vehicle speaks of a person with a spiritually poor ministry or poor motivation in life.
In the dream, this horse probably represents Jesus Christ. It speaks of the power of Christ, who was sent by the Father to judge the world. The fire speaks of judgment (In a negative sense, fire symbolizes the judgment of God. It speaks of punishment and accountability).
God wants to act in our lives but He does not and cannot until we act on his word and his will. In the dream, it is represented by your son grabbing the leash. This act set off a series of events (the flames and the explosion of the wooden trojan horse).
So God is invisible and quiet in our lives and circumstances or in times of danger or oppression until we act, and then He makes himself visible.
Take note that the horse was not pulled into the city but remained outside of the city. The high walls of the city are no problem for God, as was proven by the way that the horse of fire attacked and destroyed the city from outside those walls.
This speaks of real power, authority and strength. This city was actually completely vulnerable and did not know it until it was too late. They did not know this until your son caused God to reveal himself in his life.
All fear left your son when God started to act and judge the people and evil forces in this city. He also knew that all the destruction and judgment could not harm him. It was aimed at evil. Not at him. He only experienced the destruction all around him as one who has special favor and protection (divine protection). God is for him and not against him.
The omega on the trojan horse’s chest speaks of the end of this bad situation that your son is going through or will go through if this is still something in the future.
The three-letter word which means victory speaks of a divine assurance that this thing will end in victory for your son.
Now, this brings me to this “thing” (what this dream is all about) I do not know what this is all about because I do not know what triggered the dream.
Is your son in a tight spot now because of difficult circumstances caused by people and evil forces? Is it God warning your son of something in the future but also assuring him that He will be there to protect him and to bring those people and evil forces to justice? I do not know but I and sure your son knows. If not, then it is still in the future.