Welcome to YT Gail and Sulley.
I would get this pup to a Ortho Surgeon, not listen to your breeder but listen to your vet. Always best to be safe then sorry.
Getting him a playmate at this point of time is not a good idea, puppies will zoom through the house, wild wrestling matches, leaping off furniture in wild crazy playing, speaking from experience in once having a pack of 3 yorkies.
Have your lil Sulley checked for Luxating Pattela before getting him a BFF.
__________________ Joan, mom to Cody  RIP Matese  Schnae  Kajon  Kia  forever in my  A House Is Not A Home Without A Dog |