It may not be YOUR dog, but since it is a family member's dog, any information you learn, you should be able to pass on. Especially if you really love your brother's boxer,and the boxer breed, you would learn as much from here, and pass on the knowledge to your brother. Breeding a dog can really change his personallity. Not to mention the health risks he carries by staying intact. irresponsible breeding brings down the Boxer breed as a whole, more ungenetically health tested animals out there (boxer are prone to genetic problems), more dogs in shelters/ rescues. You said you want to rescue a boxer (in previous posts) which i think is fantastic! but i would think it to be hard stand by your brother breeding his dog, only to possibly add to the growing #'s of unwanted, sickly boxers. Please, if you are the only one doing research in your family.. do as much as possible and pass in the invaluable information. For your brother's sake, his boxer's sake, and the sake of the breed as a whole. good luck.
-Kat