Hey(((((Lucie))))
Welcome!
I have 3 siblings that use dope all the time. My youngest brother has been in and out of jail and prison so many times. My mom kept the family constantly focused on him and many years have been tainted in our family as a result.
I understand your pain and concern. At first I was always wondering what I could do to change the situation. After a while I began to realize I could not put my life on hold because of the choices my family makes. I had to put my foot down to my mom and my siblings and get on with living.
It is not fair that you are trying to get your education and having to put it on hold so your parents can bail her out or whatever. No doubt your sister is sick and needs help.
Speaking from my experience I find that constantly bailing them out and not letting them take responsibility for their actions is very detrimental to not only them but to the ones who are trying to "fix" them. My mom would plan her vacations and all holidays around getting to my brother at where ever prison he was at at the time. My sister was very young at the time and I believe she was taught that doing dope got you lot's of attention from mama cause at 40 years old she is still living at home doing as much dope as she can...My brother too is still living at home at 50 years old doing as much dope as he can and planning his retirement by going back to prison... is that sick or what...
If you refuse to be a part of bailing her out and trying to fix your sister it will not make any points with her or your parents but, it might save you your sanity...I am praying for you and your family