Is my sister being neglected by my parents?

My sister is thirteen, nearly fourteen years old. My parents are currently on a diet so they frequently don’t cook for her. She eats bread for dinner for five days a week and goes to bed at twelve/one o’clock during the weekends. She is left home alone on many occasions but our parents have taught us very little skills to be independent. Last year she nearly electrocuted herself by sticking a fork in a toaster to get some bread out. She didn’t know it was dangerous.

She’s obese and her health is poor. She has some very strange convictions that are supported by my other two sisters and my parents. Her home town is the safest and best place in the world, she idealizes her parents and wants to copy their lives exactly. Her friend has leukemia but she is praised by how she is dealing with her friend so amazingly well (to the point it nearly sounds like she is the one with cancer)and how she must struggle to keep the friendship intact. She throws massive hissy fits, comparable to the ones of four year olds, and she is very babified by the family.

She doesn’t so badly in school but I’m still concerned about her well being. I emigrated so I am not around often but based on earlier experience and when I do talk with her on msn, I seem to be raising her or at least talk a bit more sense into her. Judging on the accounts of my grandparents they also tend to sway her and force her to think more logically (For example she detested me for not making her the bridesmaid at my wedding many months ago and my grandparents told her not to dwell on the past while my other relatives persuaded her to never forgive me).

Is there any advice you, my fellow fluterines can give me? Is this neglect or am I thinking too much into it?