Open meetings mean that you can go to them even if you are not the one struggling with the problem.
Closed meaning mean the opposite.
I am a member of Al-anon and go to a lot of Open AA meetings though I myself do not struggle with alcoholism. I do not go to closed AA meetings if that is any help.
It sounds like you fit the definition of a loved one with substance abuse issues. In the meetings where I live the substance does not matter we are there to support each other regardless but there have been comments here that that is not always the case other places.
Therapy helped me too, and the combination of Al-anon and therapy did wonders.
I too found until I posted on my own that I did not get a lot of feedback. Once I did the first one though I was up and running....so welcome!