Perhaps it may help solve your friend's problem. He has only better health and well-being to gain by applying its recommendation. What has he got to lose?
These two quotes are instructive:
"There are more than ten thousand scientific papers that make it quite clear that there is not one body process (such as what goes on inside cells or tissues) and not one disease or syndrome (from the common cold to leprosy) that is not influenced - directly or indirectly - by vitamin C." -- Dr. Emanuel Cheraskin, M.D., Dr. Marshall Ringsdorf, D.M.D., and Dr. Emily Sisley, THE VITAMIN C CONNECTION.
“I have never seen a patient that Vitamin C would not benefit.” -- Dr. Frederick Klenner, M.D.
I wish you BEST success, Bill, in your search for a solution to your friend's health issue!
P.S. I also agree wholeheartedly with Dane Lady's post!