I don't honestly think that revenge will give you the satisfaction that you're looking for. You say you tried therapy, but that didn't work. Have you considered looking for another therapist? I can't even tell you how many therapists I went through before I found ones who could help! And no one modality fixed me. It was more like take what I can from one type of therapy and then find another type to help me in another way.
Have you heard of ACT (acceptance and commitment therapy)? Anyway, ACT would tell you that we all have some sort of source of pain. We only suffer when we avoid dealing with this pain. The diagram to illustrate this concept looks like a bulls eye. In the center is our source of pain (trauma). The next ring out is avoidance, or what we do to get rid of the pain. The problem is that avoidance solves nothing, rather leading to suffering. The bulls eye continues outward with another ring of avoidance because we don't want to suffer so we avoid our problems more. Outward, it alternates suffering/avoidance/suffering/avoidance/etc and the only way we can stop this nasty cycle is by dealing with the original pain.
Why do I say all this? Because it seems that you're not dealing with the pain itself. You've just been engaging in avoidance activities, so I'm not surprised that things aren't going to get better.
And what sort of revenge are you going to enact on your brother? If he doesn't care about you, he may just laugh in your face no matter what you do. Then what? Engage in illegal activity?
I think you should work on accepting what happened. I think radical acceptance would help you. Right now your energy is so focused on your brother that you're not using that energy to heal. I'm not saying its easy because its not. My process of switching my focus from being angry at my perpetrator to healing myself just about killed me. Long story so I won't go into details. BUT, in the end it was worth it to let it go because she's not worth a damn second of my time, and now she gets none.
I wish you the best.