How do i deal with my brothers disrespectful girlfriend?

Ok my brother ( 23 years old ) has a disrespectful girlfriend (22 years old ) she's constantly doing the dumbest things and has no respect or manners for anything or anyone, shes ignored my grandma before more then once, and just always has something bad to say.i mean i have a whole list of things she has done before. but the other day she disrespected my mom when she was asking her to clean the bathroom ( by the way she is from new mexico, and my parents have paid for her tickets to come to california then back to new mexico and back to california, and they dont charge her rent or any kind of bills at all its pretty much a free ride ) and she gets mad when she is asked to do anything she's even told me she dont like doing anything because its not her family even know my mom and dad are supporting her.she doesnt do anything right she does a half *** job,thats probely why shes gotten fired from two jobs since shes been here and my mom called her to the bathroom and she has an additude about it and my mom has gone thru this many times i might ask and she tells her that if she was her daughter she would take away her internet..cuz thats her life shes on there from 6 in the afternoon to like 5 in the mourning.she stays up all night and sleeps all day she has no job no car no nothing..and she says "well..i don't use the internet"..and my mom said well then i would take away your cable and she says"well i don't use that either". just being a smart ***..and i cant stand this chick anymore shes constantly doing dumb **** and making our family argue and just pulling us all aprart by the dumb **** she does...shes done PLENTY more stuff how should i go about this cuz i cant stand it anymore i have all this anger towards this chick and one of these days im not gonna be able to hold my self back so if you could take some time out of your day to help me out and give me some advice or your opinion that would bee really nice thank you !