Supported Fascism? Mises personally had to flee the Nazis. He also wrote a whole book about why fascism in general is bad ("Omnipotent Government: The Rise of the Total State and Total War").
I'm sure there are shades of gray here, but he was an adviser to the Austrofascists and wrote in support of Mussolini. He certainly actively supported fascism in his lifetime.
Mises: "It cannot be denied that Fascism and similar movements aiming at the establishment of dictatorships are full of the best intentions and that their intervention has, for the moment, saved European civilization. The merit that Fascism has thereby won for itself will live on eternally in history."
