Many of our parents here have found it useful to establish house boundaries around behaviors as well as actual substance abuse, for example dishonesty, disrespect, failure to match word with deed, failure to comply with house rules, etc.
Addicts are extremely deft at protecting their substance abuse, but this often does not translate into their being able to keep their behaviors acceptable - this is where you can often have the leverage you need to make changes in a situation if you are not able to "prove" substance abuse. (In other words, it takes away the burden of "proving" substance abuse and gives you the freedom to set boundaries and act on unacceptable behaviors within your own home.)
Just a thought, and welcome!
CLMI