No type of abuse is worse than any other, abuse is abuse, and the fact these people are downplaying what has happened is ridiculous, but unsurprising. It's what families do, trust me. It's not HIS fault of course. They make excuses, they stick by the guilty person because it's safer, it's all just cowardly. And the resentment can stick for an extremely long time. Sometimes the people who are meant to help you don't.
If they aren't listening, MAKE them listen, or find someone that will. Because they are only letting him get away with it. I really suggest you don't keep your mouth shut about it, because it can stick with you. I resent my family for taking the side of someone who beat me up when I was 15, I was treated like it was all my fault, and now it's an unspeakable thing in my family. Just excuses excuses excuses. God I hate them for it. What did I do wrong? How was it all my fault? Why is he allowed to get away with it but I say one word and I'm a terrible person?
Bare in mind that what happened to me was one incident, and it was 7 years ago, so it pales in comparison to what happened to you. But the resentment is still boiling inside of me. So I really suggest you do something, get out of there, do whatever you can. It's amazing the selfishness that can come out of people when someone needs help.