Complete apathy towards parents

I live in my brother's shadow despite him not amounting to anything. He had sickle-cell anemia and received all the attention and care from my parents until I was 14 and donated the bone marrow to cure him. I have mostly come to terms with being the ignored child due to his illness, but I am still receiving the fallout of his "popularity." I am known not by name, but by virtue of being his younger brother.

What makes this pertinent is that this is the only time I can remember anyone in my family telling me that they've been proud of me. My grandmother even said, "it was like you were put on this earth to save your brother's life." All the time I spent growing up was used excelling in class only to be greeted with dissatisfaction when my grades were not perfect or A's were not high enough. As a result, I gave up. I had done only adequate work to allow me to get by, because unless the class was a challenge I had no drive to excel anymore.

My parents have no idea how to communicate to other human beings in the immediate family. Being the youngest of the bunch I am to have no mind of my own when in their presence and must jump whenever they bark. If by any chance they are agitated at someone else, I am often the outlet and any protestation is met with, "who are YOU talking to?!"

What really irritates me is that all of this social ineptitude is surprisingly absent when dealing with ANYONE else. Older property of mine is given away freely. I am whored out for computer repair or other menial tasks to their friends without any forewarning. People who they even disdain are treated with more respect when they are interacting with my parents. The most basic nicety isn't extended to me even when they would like something done. I am given orders, never asked to do something like an actual person. Nary a "Could you? Would you? Please."

To wrap this sob story up, the crux of my issue is that whenever I had a problem or needed an actual person, I was left to my own devices or money would be thrown my way for me to resolve the issue. I am always met with this martyr-like attitude from my mother especially despite the enjoyable bonding moments in my life has not exceeded 4 hours since I was 4. My father just doesn't give a darn and a conversation is never held despite my efforts, unless my brother or someone else is there and then he has no problems conversing.

Even after I've finished college with an engineering degree, they continue to "communicate" by yelling and refuse to acknowledge my point of view and continually ask rhetorical questions.

In the end, I have no real love for my parents and most anything I do is derived from this sense of duty or debt. Even when I visit, I tell my friends, "well I have to pay my respects to the benefactors." I just wish to finish graduate school, move further away than I have already (400 miles isn't enough) and just give them sums of money and never deal with them again.

Is this normal?