宿題の義理の弟を手伝ってください

I am going to fail one of my classes and I really don't need my parents getting on at me and finding out what a failure I am. My older step-brother has done this class so I thought if I asked him nicely that maybe he would help me out so I don't fail. What I didn't know however is that he would take this as an opportunity to get something in return for helping me out. Now, I did say I would do anything if he helps me pass. I really can't afford to fail this class so I have to do what I have to do in order to pass.