All You can do is to have honest conversation and emphasize your point. What they do in their lives is theirs and theirs alone. You might have an opinion and if the friend is willing to listen then fine. But do not let this ruin your friendship, let them be. Explain your point and then shut-up about it. They know where you stand. If they need more help, they know where to find ya. I think that sometimes we try too hard. Your heart is in a good place just be a friend not a pusher, I think it will serve you better. If you are concern about your own live, you have not a lot of choices but limit your exposure. Sad but true.