In home feng shui, mirrors are very important items. They can not only change the direction of light, but also change and accelerate the direction of air energy flow. They can also guide air energy and light to achieve anti-evil effects. The function of evil spirits is to turn misfortune into good fortune and turn danger into safety.
There are three main types of mirrors commonly used in Feng Shui: plane mirror, convex mirror, and concave mirror. Plane mirrors can change the direction of Qi energy, and convex mirrors can make Qi energy emit in different directions, which has the effect of eliminating evil spirits. Concave mirrors can absorb the energy from all directions and have the effect of Naji.
Normally, do not hang a mirror outside the door, because although the mirror can block the evil spirits outside the door, it also blocks the Feng Shui wealth. This is only done when there are external evil spirits facing the door of your home. The mirror needs to be hung up. According to your story, there is no obvious external evil outside his house. In this case, if the mirror is hung up, it will only block the Feng Shui and wealth, and it may also have bad effects on the neighbors. Therefore, under such circumstances, it is better not to do things that harm others and do not benefit oneself. You can explain this truth to him clearly. I believe he does not want to cut off his own Feng Shui fortune and offend his neighbors.
If he insists on not taking it down, the best way is to make a screen wall outside your door, or use plants to place between the two doors, but this cannot completely resolve it. Hanging a mirror can only lead to a lose-lose situation. So it’s better to convince your neighbors.