I can imagine the AfD being a proxy or a stalking horse for the respectable fascists of the governing coalition, its lack of respectability being its most valuable characteristic for them, like Le Pneu's partei in France. Notice how liberals like to do deals with fascist groups rather than lefty ones? It's reminiscent of the dilemma of the respectables, once they had kicked the SPD out of government in 1930, the real end of the Weimar republic.