Fr. Wade say Evil spirits are terrified of St. Joseph because he alone is the Spouse of the Immaculata and the (earthly) father of Jesus Christ. Saint Joseph is the gateway to Jesus and Mary... He saved the Savior from Herod, spent decades in adoration, exercised paternal authority over Jesus, and made it possible for Jesus and Mary to offer their sacrifice on Calvary. Demons have plenty to be afraid of in the person of St. Joseph.
The title “Terror of Demons” is the most unique title of St. Joseph. It is a fearsome and commanding title. It is the title of a warrior. The Lily that St. Joseph holds in his hand is a mighty spiritual weapon, a sword of purity. It has the power to pierce fire-breathing dragons (that is, demons) and conquer every form of filth and darkness. The Lily he yields is a threat to all the filthy forces of Satan.
Demons are terrified at the mere mention of St. Joseph’s name. They fear everything about St. Joseph.