Family Drama

My sister is HELLA protective over my niece. For context, she is like 15 or 16. They don't let her go anywhere by herself. She has had no outings or hang-outs with her friends in her life (idk if she ever sneaked out). She is not allowed to go to any friend's birthdays and no friend is invited over at her birthdays. In conclusion- 0 outings except for with family. Oh and did i mention that they drop her off and pick her up from sch too which is not very far?

For more context- I accidently read her diary (IK ITS VERY WRONG I AM SO SORRY MY BABY BUT AUNT COULDN'T STOP HERSELF) and it make my heart sink. She does not like it at all. I did some research after that and found out all the info in the above para. As an Aunt i am kinda worried for her.

How would this affect her once she gets her freedom? Is it really serious or just a teenage thing? Should i intervene??

Is it common to be able eat anything in your kitchen? Let's say you live with your parents. You are still a high school student. Your parents provide you food right? They should right..

I'm thinking about this lately. Since my mom passed away, I've been reluctant to eat food in my own house. Because few times I ate food in my own house, someone kinda asked about the food and I felt really bad about it. It rarely happened before when my mom still alive. I know I'm spoiled asf. But I didn't realize it that my mom always give me all i want And I realized it now. Now I don't want to eat food when they don't ask me to. And it's in my own house I can't eat it. It's just feel weird to me. I'm crying while typing this. This is just hurt. Maybe there are many people who live like this since a kid, all I could say is you're strong

I am looking for a job now so I could earn money and buy food myself. I just want to vent here..