The verse "Then Tobit finished giving thanks" (Tobit 14:1) signifies a shift in the narrative within the Book of Tobit. It indicates that Tobit has concluded a period of prayer and gratitude, likely related to the blessings he's received, particularly:

Recovery of his sight: Tobit had been blind for several years and had his sight restored through the intervention of the angel Raphael and the remedy applied by his son Tobias. This miraculous healing would be a major source of thanksgiving.
Prosperity and well-being: Tobit and his family had faced hardships and financial difficulties. Through the journey of Tobias and the help of Raphael, they experienced a turnaround in their fortunes. This improved situation would naturally lead to gratitude.
Divine Providence: Tobit, a righteous and devout Jew, recognized God's hand in the events that had unfolded. He would be expressing gratitude for God's protection, guidance, and intervention in his family's life.

So, after expressing his gratitude for these events, the story will move in a new direction.