@Miraclemaker11, It sounds like you have assembled quite a team of doctors to treat your son. Is there one who has taken the lead to coordinate care? You mentioned fatigue and low blood pressure being among the most significant factors. With autonomic dysfunction, sleep can be a big problem. I have found that working to improve sleep often helps daytime symptoms. What have the doctors suggested to treat his underlying fatigue? Excessive norepinephrine activity can cause physical fatigue which in turn can trigger alpha-adrenergic rage. The problem seems to come from a failure in the rhythm of the norepinephrine cycle. When norepinephrine levels fail to drop during the night, the brain can't properly rest. This not only disrupts sleep but can cause the blood vessels to remain constricted. Then you have a cycle of low blood volume which then contributes to poor circulation, cold extremities, dizziness upon standing, tachycardia, and exhaustion. Perhaps you could ask about clonidine? When given at night, clonidine may provide a break from the norepinephrine release plus it has the added benefit of dilating blood vessels which may improve blood volume- and promote sleep.
You are correct that the autonomic system is less than completely understood by many doctors. Because it has such a significant presence, and affects a variety of organs, this complexity requires specialized knowledge. I have found that after a bit of education about what's going on, primary care physicians as well as other specialists can become great partners in helping you on your way to healing.