Am I wrong to want my sister to not ask our mom for as much money?

My sister and I are both college student. She's a year older than me. I have a full-ride scholarship that covered all of my tuition, room and board, and most of my textbook. My sister have only average grades and she's really lazy and didn't bother to research any scholarship opportunities. But she does have the $5000 Pell grant because my parent's low tax return income. She also has $2000 of grant money from the school, also because of our parent's tax return. I suggested her to apply to a scholarship that I have, it is a need-base scholarship. Since I have a lot of other scholarship, this scholarship offered me only $2000 a semester. My sister received $4000 a semester because she needs more help. My tuition is about $20000 a year and so was hers. My mom, the sweetest mom there is, was committed to give each of us $5000 per semester. We are not a wealthy family. My mom is a hardworking person and she is very conservative. She tries to save every penny that she has so she could help us with our college tuition. She won't even go to the doctor when she's sick because the medical bill would be too high. I appreciate my mom for everything she does and I don't want her to work as hard so I applied to every scholarship there is and get good grade so she doesn't have to pay anything. Now that my sister has the $8000 scholarship, it should be enough for her to pay for all of her college expense but she still asked my mom for the $5000. My sister is a spendthrift. She spends money like she's a rich person even though she grew up in a middle-class family. She originally lied to my mom that she only got $2500 per semester from that scholarship so she would seem like she still need money for her tuition. When I found out that she actually have $4000, I confronted her and told her I would convinced mom to not give her the extra $5000 because she doesn't need it anymore and she went berserk. She was furious that I would tell mom. She said that she doesn't think like I do and just because I don't take a dime from mom doesn't mean she shouldn't too. She think mom promised to give us $5000 each semester, she should still have the money no matter how much scholarship and grant she has. My argument was that our mom is not obligated to give her any money, she's only doing it because she love us, and we should appreciate her and only take what we need,. She said that she doesn't want to live like me. Because I don't like to eat out, I always eat home cook healthy meals, and i don't buy over $100 shoes, and I'm very frugal. She thinks that I shouldn't judge her because we don't think the same. But am I wrong to want her to not ask mom for the money when she's already have enough. If she wants to spend freely on clothes, expensive shoes, and expensive restaurants, she should spend her own money, she should get a job, and not use mom's money. I don't think there's anything wrong in wanting to live like a rich person and spend money on luxuries but we also have to look at our family condition. If we did not grow up in a rich family, we should conserve money when we can until we get a good job and are able to start making money ourselves. My sister was so angry that I was calling my mom to convince her not to give my sister so much money so she called me a bitc*, she was crying and yelling, she knocked my whiteboard off my door, and she even hit me. I don't think she meant to hit me but she always gets so violent when she gets mad. She would throw things around and punch things. She punch a hole through my door once but she never want to actually hurt us, but she sometimes does hurt us on accident because she's just totally out of her mind. Sorry for the long paragraph, I just really needed to vent. I think she is such a horrible person right now because of her anger issues and her violent behavior and her lack of appreciation for mom's money. Of course, she thinks I'm the worst person in the world as well. She specifically said she hates me 100%. But I really don't understand how she could act that way. I'm doing the right thing, aren't I? Am I wrong to get involve with her business? Am I wrong to want her to not take unnecessary money from mom? P.S. my mom is the kindest woman in the world and she is still willing to give my sister the $5000 even though she knows my sister doesn't DESERVE them at all!!

The best you can do is talk to your mother about it. She has the ultimate decision. At the end of the day thats her daughter and she will choose how she decides to help her. Your sister wont know what she has until its gone.