Well you've made up your mind. I understand that you probably won't read the following, but if one person reads it and decides not to buy from a breeder who would remove the pup so young, then it's worth posting it. In many states its not even LEGAL to do what your breeder is doing. But I'm sure he knows best. After all he's kind.
What age can a puppy leave mom and littermates?
That question often comes up when someone is either looking to purchase a puppy or when someone who knows very little about dog breeding breeds their female dog. The American Kennel Club recommends that puppies stay with their moms and litter mates until they are 12 weeks old. This is to insure that the puppies learn how to act like a dog and can react to other dogs in a social manner when they are older. Puppies that are separated younger than that often have behavioral problems around other dogs. All too often the future puppy owner is thinking not when the puppy is mentally able but more along the lines of if the puppy is weaned and on solid food. The backyard breeder is thinking more along the lines of how soon can I get rid of the pups and get some money for them. Thankfully many states and even localities have enacted laws to prevent puppies and kittens from being given away or sold before a certain age. Often those laws prevent people from even advertising puppies for sale unless they state the date when the puppies will be available to leave their mother. Most laws state 8 or 10 weeks as the minimum age for a puppy to leave their mother but before you, as a breeder or buyer either place or buy a puppy check with your local laws and think first of the puppy’s mental health. Above is copied from this site