Don't get hung up on the word "mother" because it could just as easily say grandma or sister the main point is no matter what your relationship to the addict - you suffer along with them. I am a mother.
I am not an authority on this subject but I certainly have lived it. Lived through the process of addiction and seen what it has done to my child and to our family.
Perhaps by telling our stories we can help someone else or at least help them in not feeling so alone.