Hi
If the family doesnt know then this would need time to sink in if they believed it from day one and you would be a bearer of bad news so to speak. Not a flattering light to be held in. Families of addicts are often in denial or bury skeletons away so it doesnt exist.
Addicts are convincing story spinners and secret keepers. They are not however capable of it in the longrun. The family will catch on when there is no Codie to play crisis manager on call.
If I had to choose somewhere to put my effort in then I would rather focus on building my future as addict proof as possible then convincing an addicts family of his doings.