Abusive Father Wants to Kick Out my Mom

My dad wants my mom to leave to Mexico by Thursday and if she doesn't he is threatening to not pay for the house anymore and will loose everything they had fought so hard for. my mom isn't in the US legally. They were married in Mexico but not here, so she has no rights? I
I am 17 years old and I don't know what to do anymore. My Dad and I have never had a hallmark father/daughter relationship. Hey, I was never bitter about it, it's just, he never just told me he loved me or was proud of me or listened to me... My Mom is the exact opposite, sometimes I feel like I don't deserve her.
Anyway, when I was 13 I found out that my dad was cheating on my mom because I read his texts. To be honest, I was suspicious, I've never trusted him. (I found animal porn and normal porn on his computer, little me thought that was extremely weird at the time)
I decided to tell my mom, hoping she would leave him, you know, stand up for herself. She did, until I guess she gave up, she loved him too much. She forgave him, but the scars never healed, and in 4 years my dad didn't talk to me about it and he knew that I was the one who ratted him out. So I have been nursing this hatred towards him all this time for his neglect and his emotional abuse. He has said I was useless and dumb and wishes I was someone else, even before the cheating thing he had always said that. Dad has installed a telephone program that copies what people say on our landline phone!!!! He's spying on us!!! Help.
Update : My mom entered the US and was caught, then she came back in illegally... i don't think calling the cops will make anything better... emotionally i don't know how i will get through everything without my mom. my dad thinks she cheated on him with the nice, young, new neighbor because he doesnt trust joe!! he made me listen to a phone conversation i had with my mom and tell him whether or not it sounded like she was having sex? no it f*cking sounded like she had been crying!!! that's all!
Update 2: She would never do what he did to her. Also, he gets drunk often and won't eat so he wakes my mom and me and my little sister at 2 AM and shines a f*cking flashlight on us!!! (my mom, me and my sister sleep together now.) I kick him out and then locks himself into our car with two of his handguns... i dont know what to do. HE WONT LET ME LEARN HOW TO DRIVE BECAUSE HE KNOWS ILL LEAVE HIM. i dont have a job and i am so helpless, if my mom leaves... ugh idk what will happen! he sometimes collapses
Update 3: after drinking in tears and scares me and my sister so much, shes 10. Her name is annie and she adores our dad because she is completely oblivious to what is happening. maybe this whole thing won't emotionally scar her like it has me ... i just hate myself sometimes for being so helpless and sad and depressed all the time. how do get help when everybody is screwed up around me?