Being compared to your brother isn’t his fault. Don’t take it out on him.

Comparison is done to both of you by somebody else. Relatives, coaches and teachers set two siblings next to each other for their own convenience, and the resentment it generates has nowhere obvious to go, so it lands on the brother who also did not ask for it who may be getting the same treatment from the other direction. He is not the source. He is the other person in the room when it happens.

If this is happening, aim the irritation at the comparison rather than at him, and you can say that to him directly. Naming it usually turns the two of you into allies instead of rivals.