Hi don, I dont think Ive ever read anything that says that people with me/cfs have high magnesium levels, Im a Kiwi to, and I know how crap the medical services can be over here, so Im wondering if your family members have been given the right diagnosis!!
On this link it tells you quite a bit about what the magnesium tests can mean and what other tests should be done as well to help find the cause of your family members high magnesium
http://labtestsonline.org/understanding/analytes/magnesium/tab/test
This site is a diagnostic software site, for high magnesium it lists these conditions as possible causes of high magnesium
http://en.diagnosispro.com/differential_diagnosis-for/magnesium-lab-increased/10420-154.html making the assumption that your family members have chronic fatigue if you add that to high magnesium you get these 13 illnesses as possibilities
http://en.diagnosispro.com/differen...ased-chronic-fatigue/10420_25271-154_154.html If you click on the names of the diseases it will give you more information on the kinds of symptoms they have which may help you narrow it down.
This site is free if you want to learn how to use it and enter your family members symptoms and any other failed lab tests they may have, it explains how to use it here
http://en.diagnosispro.com/diagnosispro_help/generate_a_differential_diagnosis_list/
A lot of these conditions like Diabetes, Addison and hypothyroidism are often mistaken for me/cfs, so if the doctor has not ruled all these out they need to!!! your doctor should also be thinking along the lines of genetic illnesses as well, and maybe something that is more common in females.
Dont trust that your doctor has given the right diagnosis until every possibility has been ruled out, a lot of people get misdiagnosed with me/cfs and suffer needlessly for years because of it, Hope this helps in some way, must be really hard having so many in your family sick all at once.
All the best