One of the main points of Taoist philosophy is the middle way: being mutual and finding the balance between yin and yang. In the process of obtaining the middle way, firstly one needs clear understanding on these two polarities, and then deep cultivation/healing work on two opposites: Light (yang) energy and dark (yin) energy. As a human being, we all have these two and cannot avoid one or the other.
If one is drawn to light energy with attachment/or obsession, it may be seemingly better than for example substance abuse/obsession. But what will happen is that the underlining dark energy is pushed away for a prolonged time and builds up inside, eventually it will bounce back. One will fall apart mentally, emotionally, and even physically. It is like the Sun, when the Sun is brighter in noontime, the shadow/darkness is more intense and sharper.
The parallel healing means we walk on two tracks of the healing path (like walking smoothly with two feet). The light path includes any correct spiritual practice such as Taoist Light Qigong, receiving the light energy, empowerments, and bliss; while the dark track is working on the underlining dark energy: negative thoughts (doubts, confusion, and obsessive thoughts) and feelings (anger, sadness, and fear), bringing deep healing to the painful memory that the mind and even physical body still remembers or reacts to.
Qigong practice can bring the dark energy out to surface for healing. When the dark energy surfaces, we observe it consciously and dissolve internally; or with support through people who will not be affected by it, also remember the practice of endurance so it will not become out of control and even a negative force to others nearby. When it comes out, it is the time to see it clearly and work on it, so the pressure/suppressing energy can be released and dissolved. The result of this will be: the person will become more healed and authentic (inside and outside maintain the same energy frequency, otherwise outside appears calm, but inside is turmoil), and become a whole being.