My friend progressed a bit now in the story of Pokémon X & Y and now, he's blocked (He did not tell me where). Apparently, he needs a Rhyhorn. He has got 2 questions:
Thanks for your help.
You don't need a Rhyhorn to progress through the game though you need to ride on one. But the game already provides Rhyhorn's to ride on so there is nothing to worry about. Btw Rhyhorn isn't the only Pokemon that is to be ridden :P