If he doesn't practice proper quarantine procedures, he should. Seeing as it appears he is trying to make a business name for himself, that would shine rather poorly in his favor. It is a breeders responsibility to make sure the animals they sell are healthy and disease free. If you want to make it more basic than that; it is a keepers responsibility also.
Some people simply don't know about why they should quarantine and need to be educated. Whenever I add a new addition to my collection; the animals get a veterinarian visit with a full checkup and a fecal. They also get six months in quarantine at the other end of my house. You can never be too cautious with boids.
That being said, they are very attractive animals. I hope for their sake, you do quarantine them for a minimum of three months.