The discovery was made on the granddaughter's cell phone. Her parents were informed and my immediate reaction was, "Contact the parents of the friends and let them know." The grandparent seemed hopeless and helpless because she didn't feel it would do any good. We often hear about parents who allow underage alcohol use by their teens as long as it happens at home. The mistaken assumption is that this course of action is safer due to the parents knowing where their kids are and what they are doing. We all know what the research says about early alcohol and substance use and the effect it has on the developing brain. Either parents choose to ignore these facts, or they believe it won't happen to their kids.
Unfortunately, there is no easy answer to this dilemma. As parents and grandparents, we can no longer choose to only be aware of our child's actions and decisions. We have to now engage other parents and be aware of their beliefs and decisions about their teens and underage substance use. It's a challenge, and social media, depending on our approach, can make it easier or more difficult.
A few resources do exist. Our own website, I CARE, has a digital guide for parents. Lots of information can be found at Partnership for Drug Free America. In fact, an excellent article at this link debunks so many of the myths associated with underage drinking at home.
Even though it is filmed in a different state and jurisdiction, the video below sums up my perspective perfectly on the issue.