I am writing in as a Boxer breeder to give my imput on the situation. Undescended testicles are not an indicator of a poorly bred dog. It happens. I personally always do check though because when they are 8 weeks of age you can very clearly see them start dropping. The breeder should have checked and told you but I have a feeling this person might just have no idea when they are supposed to drop. But, again, this is not an indicator of poor breeding habits. I'll tell you what IS an indicator of a good breeder though and that is disclosing a dogs temperament and placing them into appropriate homes. Female Boxers tend to be more dominant (not all, but most). What a good breeder should cover are congenital diseases such as severe murmers. It's basically anything that puts the dog's life in danger. I always give a 2 year health guarantee in writing against life threatening diseases. I'll tell you this though, if someone came to me with documents from their vet stating that the dog's life was in danger due undescended testicles and I was given a chance to talk to the vet to confirm this, I would give a refund or exchange. But, this is probably an unlikely, probably rare circumstance. I don't know any breeder that will cover cancer only because it is not strictly genetic, environment has a lot to do with it. A good breeder will also give new buyers copies of all of the parents health testing results (if they don't test, dont buy!). As far as neutering, I recommend between 6-9 months but that is only because after that timeframe is normally when a male learns how to spray (though some take longer to learn this of course). Once he knows how to spray though, neutering will usually not stop it and spray stinks! I always put on my spay/neuter contracts that the new owners are to have their dog fixed no later than 12 months of age, but if someone has a problem with that due to medical concerns I have no problem extending it out. I would talk to your vet about the puppy to see when it would be best to neuter him due to his condition. Sorry so long. I hope this helps!