If you signed a breed back contract when you bought the dog then she has the right to breed him. If it merely states that you can't breed or neuter him and nothing is mentioned about her having breeding rights, then she needs your permission to breed because like a female that gets pregnant against the owners wishes, it can be considered damage to property. However, if she plans to breed him while you are gone and before he has had any kind of genetic health screenings/certifications or temperamant tests/certifications, then she is being irresponsible and should not be breeding period. It already sounds like she is irresponsible if she sold a dog with a breed back contract to a family that doesn't show their dogs. A reputable breeder that sells a show/breeding quality dog will usually sell it to another show person with a breed back contract because they know the dog is going to be show quality and have the ability to win titles. It would be pointless to sell a show quality pup to a family just wanting a pet. If you can't trust this person, then the dog doesn't need to stay there. One way you can tell if a male dog has been bred is how low their testicles hang. The more they've been bred, the lower they hang.