About the "psychological"--that usually is the bs given when the doctor doesn't know why something is happening and is too arrogant to admit it.

Interesting about the low blood pressure as our family member with sleep disorder has very low blood pressure as well. But also multiple other strange things going on.

Unfortunately, not every source is identifiable. Is the sleep disorder from the low blood pressure or the low blood pressure from the sleep disorder? Is there a problem in the hypothalamus or endothelial production underlying both conditions? Is it a mitochondrial defect or dysfunction? Is it an autoimmune problem? If so, what was the underlying weakness leading to that?

If all else fails, go to an MD specializing in integrative or functional medicine for a whole-person approach to treatment.