How can I help my mother?

On the morning of September 20th, 2006, my father, Patrick Sullivan, had died. The day of his death and the day of his funeral were as of yet the worse days of my life, it still feels like it all just happened yesterday. I love my dad, and I miss him so much. But one year and six months after that, my mom started dating one of her childhood friends. I do not like the idea of my mom being with someone else other than my dad. All my life, my mom had always seemed to be an emotionally, strong, independent woman, and I was convinced that she loved her husband so much, that she would never replace him with anyone else, but I was wrong. I recall her saying that we would not become one of those families who forget about their fathers. I do not like this guy; he's rude, ill-mannered, and very loud like a redneck. He also fights, drinks, smokes, and cusses like an animal. My own home has become a living hell, especially during my final years of school. Every time that guy is around, I feel like I turn into a monster inside, metaphorically speaking. I don’t want another father, because I was perfectly happy with the one I had before, my real father. The way I see it, this guy is no better than my dad, yet he’s trying to take his place by sucking up to everyone so he can be loved by my family. Luckily, I still have some people on my side; they’re just not saying anything so they can avoid conflict and confrontation with my mom. I don't like being anywhere when he’s around. However, when I’m far away from him, I feel happy. The only way I can get away from all of this is to go outside for a walk for a couple of hours or go to a friend's house or a relative's house, or school, or my job. Because of him, I’ve even become resentful of my own mother. I’ve always felt that she understood me, but for once, she actually really doesn’t. She has started arguments with me, involving her having yelled at me, calling me names, making me feel guilty, saying I’m evil, slapping me, disrespecting my dad, almost everything in the book. Recently, she has said that I’m not the child she raised, and I’m starting to think that she’s right. She never raised me to believe in having step-relatives. The only thing that’s gotten to me so far is the time when she said that my dad never loved any of us and having him die was the best thing that’s ever happened to us. My mom has changed for the worst, and there’s nothing I can do about it, all I can do is keep my distance and move on with my life. Whether or not what I’m doing is right or wrong, all I know is I love my dad, and I will never replace him, no matter how much people say my mom isn’t replacing him. When I’m at home, I ignore it all by watching TV and movies, playing video games, listening to music, and turn on the stand-up fan in my room. I’ve just recently learned that he is also the violent type. He beat up his brother just because he was using my blanket for one night. I never said he could use it after it got done being washed and dried, but he figured he could win me over by fighting for me with his brother over a blanket, which is retarded. Also, I never noticed it, but my Aunt Cindy told me that he strangles my mom, she claims to have seen strangle marks on her. It gets worse one week before school started this year, when he’s actually beaten up my own brother. He got mad at him just because he was eating downstairs in his own room. He just continuously kept calling Shawn a dumbass, until Shawn finally snapped and yelled “**** YOU!” and they started a fist fight. I feel ashamed that I didn’t do anything about it, but I feel like if I did, it probably would’ve ended much worse than that, I probably would’ve done just exactly what he wanted me to do, and I would’ve gotten in really big trouble. This freak has caused me so such pain, misery, and difficulty in my life, I refuse to look at his face or listen to his god-awful voice. Maybe for the past year, I’ve been thinking that with my dad gone and all, my mom does need a new man. Recently, he got drunk one night and ended up yelling at my little sister and hurting my brother, so we banded together and took initiative by getting help from our relatives and the school to kick him out of the house. So here's the question: how can I help my mother forget about this freak and get her to find a new man who is a hell of a lot better?