I'm glad they're handling it well and she's getting the surgery she needs.

IMO, it would be very very unlikely that any dog from a good breeder who tests their breeding stock would develop luxating patellas at such a devastatingly young age. Did they get a contract with their puppy? A good breeder also guarentees against genetic complications (including luxating patellas) for at the very least 1 year, preferably 2 or more, and will either pay for the surgery or pay the owner back for the price they paid.