<human>: Provide a brief overview of the text.

My sister is a senior in high school. She has already gotten into a few colleges. However, her grades have been the worse ever. She got 1 F her first semester, and now in her second semester she has 2 F's in important classes. It's not for lack of ability. She skips class, doesn't do homework, and basically gives no fucks.

My mom is really struggling with her. She has met with multiple teachers and counselors about her grades to no avail. My sister regularly yells at my mom when she questions her grades. This is on a daily basis. It's to the point where my mom is having horrible anxiety over my sister graduating. It's not healthy and I'm seriously worried about my mom. 

We told my sister a million times that colleges can take back admissions if you flunk senior year, but she doesn't seem to think it will happen to her. As her sister, I feel like if she fucks up, it's her mistake to live with. I'm more concerned about my Mom, who fights tooth and nail to get my sister on the straight and narrow. I'm worried she's going into depression over it. 

What can I say to my sister to get her to stop abusing my Mom and give a fuck? Do I have any say in it?
<bot>: sister is failing multiple classes, doesn't believe she can have her college admissions rescinded, verbally abuses my mom over it. Can I do anything?