I think you are right to be concerned. My Husband is addicted to Pain Killers and what happend to Heath Ledger lays in the back of my mind every day.
I have heard that Lunesta can be addictive. I'm no Doctor so I'm not sure about what to tell you about the combos he is taking. Maybe you can call a pharmacist and ask them about the combination or maybe call the drug companies and ask them.
One thing for sure is this, no matter what you do you can't stop them from taking whatever it is they are taking. They have to reach that point on their own.
Maybe someone else on here will no more then I do.