Denise and Gary Cullen hope that what happened to them does not happen to you. But if it does, they have already formed a group to help: Grief Recovery After a Substance Passing (GRASP).
You can read a short description of what lead them to do this:
At their website you can find a list of chapters around the country which will welcome you to help you.
They are currently working to form a few more organizations: Broken No More, and Moms United to End the War on Drugs. Once those come online, or I can locate more information, I'll link to those as well.