One thing I notice is Miracle-Mineral-Supplement is not yet listed as an alternative cancer treatment on the CANCER TUTOR site. Some have had success with it and cancer but it might not be the best treatment. For brain Cancer you have to be more careful.
Remember not to tough it out if any symptoms develop. No, I don't think he will directly be injured from the Miracle-Mineral-Supplement as some fear mongers would have you believe. Unless the tumor causes problems if too quickly destroyed.