With Lady B taking a day off to accompany Boatcrash to his surgery, she enlists Cheapy as a replacement vet. He likely volunteered because he was bored and had nothing better to do. I'm pretty sure as long as he follows the checklist he was given, he's fully qualified to be a substitute veterinarian. No one may get operated on that day, but he's prepared to give out plenty of literature on alternative pet therapies.
