Hi Jilly:
I personally don’t have any experiences with these fabrics, but perhaps other knowledgeable people on this site can provide some feedback.
There is some good general information on sheets and bedding here.
Regarding copper and its healing claims, here is an article that discusses that.
Copper is encapsulated and currently used in some foams (like some latex from Talalay Global), more for the small additional amount of heat transfer that it can provide.
Phoenix