My wife and I are worried about our 25-year-old daughter who has problems sleeping. She's out almost every night drinking and then takes sleeping pill?

Problem's not sleep. A person who is out drinking then taking sleeping pills to sleep isn't having problems with sleep; it's a problem with alcohol. She needs professional help with her drinking. Have her see her doctor as soon as possible.
Very dangerous. One should never mix alcohol and sleeping pills. There have been many high-profile people who have done that in the last several years who are no longer with us. A frank discussion about the risks with your daughter is indicated. Mixing sleeping pills and alcohol is extremely dangerous.