Sad to say, this if a common occurrence when you adopt two males from the same litter. Either they grow up to be totally dependent on each other and can never be separated, OR they are in constant contention. How old are they? Have they been neutered? If they are over 6 months old they need to be neutered. This will help reduce the aggression.
However, it is not the cure. You need to find a behaviorist NOW! Don’t just pick any dog trainer – look for one that can come to your home and work with you there. Or one that specializes in aggression cases such as this. And sad to say – the only answer may be that you have to find one of the boys a new home. They may have developed such a dislike of each other that they will never live comfortably together.
You do desperately need help! But it is far beyond the scope of this forum. You need hands on help from a professional that can see your dogs and figure out what triggers the aggression. And in the future – remember – never get 2 puppies at one time!
i am not an expert, but i think you should take him to vet immediately