I've plenty of fakies in my time, and many of them have been quite impressive, as the counterfeiters have evolved well beyond crappy, misspelled bands and coloring that comes off onto your fingers. And yes, many genuine Cubans have large veins and crooked bands, so you cannot really count on just eyeballing them to tell.
The real hints here are 1) He didn't buy it from a reputable source, 2) it came in a 25 count box, when Behikes only come in 10 count boxes, and 3) the price was too good to be true.