Maybe her dad thinks Daniel is a demon since he used to study demonology...thats why they won't let her see him.More interestingly, Bree revealed that her father was studying, while at Oxford, the works of the 16th century Dutch physician and demonologist Johann Weyer, also known as Piscinarius. Weyer advocated against the persecution of witches, but held that demons were real and could be forced to create illusions. He also prepared an extensive listing of demons and their powers, and believed they could be summoned to serve good if called in the name of the Trinity.
Also since demons can create illusions..maybe all this "nice" daniel is all a charade?