Is there a history with the court system with your ex?
My ex tried to impose no drinking etc. with my visitation.
It was tossed out due to no recent alcohol offenses .
Was is his DOC? Alcohol is harder to sneak then controlled substances.
How old are your children? Are they aware of a substance abuse problem with their dad?? The children if their old enough would be your best defense in the court system.
I pray this goes well for your children's sake