Frederick was an old friend of Alfred Pennyworth.
Frederick met Alfred when they served in the British Secret Service together. The two worked together often and became close friends. They occasionally called each other "Freddie" and "Alfie", though they disliked having these names used by anyone else (in fact, they may have used these nicknames as a form of danger signal, each knowing how much the other disliked it). Alfred and Frederick were each entrusted with one-half of the access code to Project Excalibur.
Red Claw kidnapped Frederick in order to retrieve those codes, and forced him to lure Alfred into her grip too. She needed truth serum to get the two to talk, but after it was administered, Frederick gave his half of the code up almost immediately. It took considerably longer to get Alfred's half, but only because Red Claw dismissed his words as delirious doggerel.
When Batman and Robin stormed the castle, Alfred was able to get himself and Frederick free. After all was done, Frederick asked Alfred to re-enlist in Her Majesty's service, but he declined politely.