discipline - HELP

I have an 8 year old sister. I left her for college when she was 3 yrs. I have no idea how my mom discipline her all these times, but she would become so ignorant and have no initiatif even for her self. However, I'm trying to fix this. as much as possible I try not to make her fear me, but sometimes I reach my limits and end up scared her in order to get her attention and obey.
Right now, my mom stress about how she would take money from my mom's room/bag/wallet for her shopping. I admit, that we never give her allowance or money, but we always give her snacks, or anything she needed instead. We purposely do that, so she won't buy snacks outside, that would make her sick (she gets sick easily). After she steals, she lies. It hurts me, this happen to my own sister. I really have no idea how to deal with this or how should we treat this problem. I always think that this probably an impact that her friends bring to her, and it make me feel like she needs to move to another school (better one with high discipline). really, is it necessary? where should I start to fix this?

MissYou

hi friends in thailand or whereever you are,

In times like these ... I miss you all , I miss our bounding times , I miss our crazyness , I miss everything about us :(

I miss you ... I miss you ... I miss you ... muahhhhh

*hug*