Well only bad breeders breed mixes and use the word teacup which means its very doubtful they do any health testing, don't care about there lines to know if Liver shunt, Collapsing trachea, ect is in them and if they do they wont breed that dog. A reputable breeder breeds to better the breed and sense "morkie" is not a breed you can't do that with them and with a mixed breed you never know what your going to get. If certain illnesses are in a dogs history they can pass them on no matter what breed they are and no mater what they are bred with. A lot of people will get there pure breed dog from a byb or a puppy mill and then that is what a lot of people see when they go to petsmart or a pet event, a poor breed or sickly looking dog and when you see enough of them you start to think well that breed must have issues when really it is how there bred. Every breed has its issues. I think he needs to look at puppy mills and see how terrible they really are to the parent dogs and maybe that will change his mind about looking for a good breeder. Make him watch the videos on this link
http://www.yorkietalk.com/forums/gen...ppy-mills.html if watching these videos doesn't make him feel bad for the dogs in puppy mills and want to not buy from them and keep them in business then you have some bigger problems.