Things like this always get dubious when people start claiming to have 'invented' them. Your description sounds a lot like any Wiccan or ritual magic path. Tends to be men who write these things, usually divorsed or unhappily married ones (ouch, cheep shot). Take it we're not talking about the Green Party's Victor Anderson?
A quick etymological search lists: "1590, var. of fairy (q.v.), probably existing in M.E., but first attested in Spenser's "Faery Queene," where he used it in his own sense, to mean "the realm of fairies," in a dignified and poetic sense divorced from the common folk tales."
So then I looked up 'fairy':
"c.1300, "enchantment, magic," from O.Fr. faerie "land of fairies, meeting of fairies, enchantment, magic," from fae "fay," from L. fata (pl.) "the Fates." In ref. to a class of supernatural beings, the word is used from 1393."
So both words appearing to be of Latin origin. Be interesting to see what the Celtic vocabulary would have been. The closes I can think is sidhe, as in 'bean sidhe/banshee', recorded from the 1700s. However the word for fairy itself is probably much older.
The reason I suggest looking back to the Celtic route is that Fairy Lore was, until not long ago, incredibly strong in Western Ireland, however you'll find it as the basis of pretty much all superstitions and folklore of Ireland, Cornwall, Scotland and many rural areas of England. It pre-dates the Roman Empire for sure, although I belive the word 'goblin' or 'gremlin' derives from Latin or Greek for a house spirit, a sort of fairy. Professor Ken Dowden wrote about this I think (as I heard him explaine this one at a PA conference in 2005.)
Back to fairies though...there's a story that as the Irish gods like Lugh and Lir were dying out and growing weak, they sought shelter from the coming invaders by running off into the hills and hiding in caves and streams. Their power was much depleted but, being magical beings, they didn't just die and lived on as 'sidhe folk', or as we call them 'elves'. So an elf in Ireland basically the ancestor of the Tuatha de Danann. That's part of what 'fairies' are there.
The concept of fairies underwent a huge revival and overhaul in the Victorian era (as did much of Britain’s geography, morality and common sense). Conan Doyle, the Theosophists and all sorts of people helped feed the notion on 'flower fairies' and so forth. Not a bad image but a slightly twee one of many.
If you want a really brilliant introduction on the root origins of fairies, I highly recommend
this book. Yes, it's beautiful to look at, but the introduction is very well written. The guy has looked into the origins of fairies/nature spirits/imps/pixies/you name it all over the world in many different cultures. It's interesting stuff. These are the basic spirits of the land and the genius loci of humanity, not just a British phenomena. Often fairy lore is strongly hooked up with local sites and traditions, especially wells - a lot of books on wells and springs will mention fairy lore/folk lore and it's often possible to determine by the Christian name of the well/spring what the place was used for before.
Fairy lore is part of all rural folk customs and folklore, has been for hundreds of years, possibly thousands. May seem nice and light but it's pretty primordial and very earthy. I think the guy you mention sounds a lot like a modern revivalist trying to make a name for himself in the occult field. But I’ve never read any of his work so there we are then, perhaps I’m wrong and he's a pretty genuine fella

Best wishes,
Marion.