Can two brother kittens live together once they become adult cats if they are both neutered, or will they not get along?
Male cats can live together. It would probably be best to get a kitten instead of an adult because the kitten won't try to make your home his territory. Adult cats will fight more together. Also if your cats are neutered they won't spray or shouldn't spray over territory. But if it isnt possable, and you have two adult male Neutered cats then they should be okay if you slowly introduce them.
DWW! I would think they should be fine, especially since you're bringing them up together!