I am looking for some sensible, non militant MN advice please. My son is very friendly with my friend's two sons. My DS has told me about some things they have done recently which my friend is totally unaware of. They are all adults in their 20s so most of it is their business and they can do what they like. Think excessive gambling etc (don't want to get into too much detail). Anyway one of them still lives at home, the other doesn't. I have become aware that the one who stays at home has drunk driven a few times (he had form in the past which my friend knows about). My son has sworn me to secrecy, said if I ever say anything he would never speak to me again so I can't open that can of worms. The last time he was out DS took the car keys off his friend so that he couldn't use them. Advice would be welcomed.