In the course of his therapy Franklyn repeatedly (and unsuccessfully) tries to befriend Hannibal and seems increasingly drawn to him. He approaches him during an evening at the opera and in therapy mentions having seen Hannibal buying cheese, trying to point out that their mutual interests would be a great foundation for a friendship.
He also confesses to Hannibal that he believes his best friend, Tobias Budge to be a psychopath and later on correctly suspected that he is responsible for a series of murders.
Franklyn is killed by Hannibal Lecter during a therapy session interrupted by Tobias Budge who admits to several murders. While Franklyn tries to convice Tobias to give himself up to the police Hannibal approaches him from behind and snaps his neck, Tobias Budge commenting: "I was looking forward to that", and Hannibal answering: "I saved you the trouble."
Interestingly, Franklyn's last name, Froideveux, is a slight deviation of the family name Froidevaux, which is common in Eastern France and the Suisse Romande. The word 'vaux' in the original version means 'you are of value', whereas Franklyn's fictional family name includes 'veux', which is translated as 'you want'.