How to remove inferiority complex?

I feel like my younger sibling has an inferiority complex towards me...I don’t know what to do. She is pretty much healthy (excluding her complex). The reason I feel like she got it is because she hates studying. She won’t turn any of her assignments in and will cut class if she has the opportunity. My family and I feel like it is unacceptable (with how hard it is to find a job and have a steady income). My mom and I are realists, but my dad is more of an idealist. He tells my sister that it is fine and she should just learn skills for a job. My mom and I find that unrealistic but we stay quiet. My mom on the other hand, puts like 90% of her time helping my sisters hw and stuff. But since she won’t put in effort, there is an endless cycle of scolding and yelling that is directed towards her. But if we don’t, she completely ignores schoolwork. We don’t even push her to be above average anymore...we only want her to pass school and graduate from high school. I am now busy with school, but even if I helped, I can tell her complex is worsening. I don’t want that...she has the capability to go higher. Modesty is pretty important in our family so I don’t go and talk about my accomplishments. However, I am not willing to bring myself down for her sake. I also have a life to live and I prioritize myself. At the same time, I want to help my sister and let her come out of her inferiority complex. I thought I had enough of coping with this and wanted to hear from other ppl. Thank u so much for reading if u read all of this.