Welcome to the SR family
I am sorry about your sister. I hope you will make yourself at home by reading and posting as much as needed. We are here to support you.
I have not lost a sibling to alcoholism, but I have lost friends.
I have benefited from reading self-improvement books on grieving, from Alanon meetings (admitting I was powerless over alcohol), SR and sharing my feelings with a social worker/friend.
Let us know how we can help you during your time of grief.