Second, the word "Helvetica" is trademarked in reference to a font or a software program relating to fonts. So unless he plans on selling a font called Helvetica, he can write the word as much as he pleases. It's the Latin name for Switzerland.
Third, until you trademark the term Helveticards and he starts offering a product in a similar likeness, this discussion is between him and Linotype. Stop trying to peddle your own product. Too bad, because I actually like your cards!