Khrea,
What age do you teach? I am so jealous that you have three more weeks... I go back next Wednesday!
If you teach older kids, say middle or high school, why not use any instance where they bring it up as a chance to tell them what kind of impact those types of choices have on their families and friends? You'd be teaching them the importance of taking care of themselves, plus removing any question of your involvement in your son's actions.
Besides, three weeks is a long time when you're talking about the memories of kids. They probably will not think anything of it by the time school starts. I know what you mean though... us teachers can be so gossipy sometimes!
I really hope you feel better soon... dealing with this extra stress while trying to enjoy your summer is no fun!