It doesnt really matter I believe, he is only going to get 48khz out of his iphone.
Unless he uses the Apple camera connection kit and inputs to the Hifi-m8 usb-B.
As of now he is just using standard cables.
*please do correct me anyone if i am incorrect here.
You may be right unless that interconnect cut up a cck and usb-b while retaining whatever chip apple put there.