
I don't feel that you can compare buying from a puppyfarm to adopting a rescued dog.
When people promote health testing and the other things you've listed it is in part to ensure a good pup, yes, but it is also because the purpose of breeding is to better the breed...not produce puppies as a source of income.
Just as you research a breeder, you should also research a rescue. What type of assessments do they perform? What information do they have available on the dog you're interested in? You cannot walk blindly into a rescue and choose a dog because you like the breed or the look. It is up to the individual adopter to inquire about the animal.
As a proper breeder should ask questions of a purchaser, a proper rescue asks questions of a potential adopter. Applications are filled out, home visits are done...all to ensure the dog is being matched to the correct home. The goal is to make sure the dog will have found the place where it will live out it's life, not be returned or let loose.
Did your friend ask if the dog had known health problems? Did he ask whether the dog had been properly vetted, etc.? If he did and the rescue centre lied to him or misled him in any way, there may be legal ramifications if he wants to go that route. I understand that some people do choose rescue because it's a cheaper route however, whether a dog is from a breeder or a rescue, a dog will always need food, vet care, etc. Some, unfortunately, more than others.
(Proud owner of 4 rescues and director of Boxer rescue) ;)