Hi, klekota. Welcome.
Very sorry for the situation that brings you here.
I recommend Al-Anon and/or Nar-Anon meetings if you are not already going.
They are fellowships of deep support for people troubled by a loved one's drinking or drug using.
They are not there to help "cure" the addict. They are there to provide support and tools for living for you as you navigate this dismal situation.
It sounds as though the family dynamic re wife and her mother is a bit of a mess.
Enabling all over the place.
You can't change or control your wife's behavior, as you know.
You can change your response to it.
I think it is very important at this time that you gather support whever you can. Friends, your family, counselling, Al-Anon, etc.
Living with an addict is a lonely business, especially when there are children.
I hope you will find some measure of support here.
Keep coming back.