Been waiting to see this figure pop up on here. First read up on him years ago, Cowan seems to represent an emerging formula of new age yuppy-hippy. Apparently a number of these figures were really welcomed into learning some of Huichol ways by traditionals, but I would certainly doubt the Huichol authorized any of them to go and start marketing it to other whites, mixing it up with a bunch of misrepresentation and stereotypes, and turning their ancient ways into a colonialistic, consumer-culture, profit-scheme.
The similar formula is practiced by a guy in Portland, OR. Apparently having spent some time with the Huichol, learning songs and about some traditions, decides to start selling himself as a 'shaman', etc, and also calling himself a 'Heyoka' and mixing it all up with various 'red road' stereotypes and other stuff, even getting money from the state to teach this stuff to at-risk youth, inmates, etc. These clowns start organizations and spread the new age all over the place, and never does it benefit the traditional community they rip off.
There are others who seem to be doing similar, and it seems to often begin with claiming to be practicing Huichol shamanism, and it often gets mixed up into appropriated Lakota and/or Plains style mishmash also. The more one studies and deconstructs new-age habits, it becomes clear there is emerging or established patterns. And to be honest, it feels very similar to deconstructing the brainwash histories and anthropological theories one must deal with in academia. It often seems the link is that, underlying these patterns, are very similar misguided and arrogant assumptions.