I am sorry but he definately is a fraud. Note that none of his parents and grand parents are listed, as is usual for ANY royal person (or even for many non royal persons) on wikipedia. The wikipedia article stays very vague about his anscestors though. The ones he does list, an Archduchess Maria Victoria, spanish Bourbons named Alphonse, Constance and Catherine (not exactly Spanish sounding names) are fake.
There is indeed a cadet branch of the Spanish RF, which received the title 'Duke of Seville', a title they still use. But this line never married a Habsburg AND the genealogy can be checked
here, on Paul Theroff's online Gotha. Look at the descendants of 14c) Infante Francisco de Paula, duke of Cadiz. No Charles is there (and considering it is a Spanish duke I suppose Carlos would have made the fraudulous claim less obvious)
Furthermore, there are several mistakes in the wikipedia article that makes me believe that this is a person with a vivid imagination at work. Several errors in titles, style etc, and esp. the claim to have been on the best dressed list of Vanity Fair and one of the sexiest men alive seem far fetched. And it should be easy enough to check, after which we will find that this person was on no such list as he does not exist. He is also rather original in mixing titles that have never been mixed. Sadly this happens every so often, there is a person online who dedicates much of his free time claiming he is the rightful king of Prussia for example, and some years ago he spammed this forum with that information.
Now, I suppose somebody should contact wikipedia about it
! 
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