You are a very brave man. I am happy for you that you have had your ‘God-moment’ where you realized that your life has meaning and you do not want to destroy that meaning with drugs and drink.
I learned long ago that people who have these addictions want to destroy a part of themselves, and that is the motivation for the addiction. They hate that part of themselves so much that they will do anything to destroy it. They do not realize that in the process they destroy every part of themselves.
Your parents and your sisters have that pain inside of themselves that they are not ready to face. You have a similar pain, caused by their behavior, but the difference is that you do want to face your pain and that is why you wrote this request for help.
Our first instinct is to judge p:eople who cause us so much pain. However, the first commandment in the Bible (even before the Ten Commandments) says "You are not allowed to eat from the tree of the knowledge of good and evil". To me that means "You have no right or reason to judge other people, because you have no idea what is happening in their lives"
So if we have no right to judge them to make us feel better, how do we deal with it? At the moment you feel much emotional pain and stress because you focus on the negative aspects of their behavior.
Have you ever thought about the positive outcomes of their behavior? I want you to make a list of all the bad things about your mother. It would be good if you can list at least 30 bad things. When you have done that, list the same number of good things about her. You will have to search old memories and recall stuff that you have forgotten, but you will find those good points. Do not stop until you have an equal number of good and bad things you can say about her (and do not cheat by deleting some of the bad things when it gets a bit challenging to find the good things!)
The result will be that you will realize how your mother's behavior has changed you for the better, and has helped you to become the person you are now. You will be able to thank her from the bottom of your heart for the valuable things she has taught you, which you have not realized until now. Then you do the same exercise for your father, and for each of your sisters.
People behave in ways that we find really hurtful, until we realize that they are in fact our greatest teachers in life. Somehow, when we reach that realization, they stop their behavior without us even saying a word to them, because at an invisible level they understand that they have achieved their purpose with you and you have learned what you needed to learn from them. Heal this division in yourself, and the healing will impact your entire family.
Blessings to you, brave man ;-)