I work with this population every day. They come from all walks of life, have all kinds of faith, have experienced terrible abuse, or no history of abuse at all.
1. None of this is your fault. These things simply happen, an artifact of our world we live in. You're both loving parents and it's clear you've been amazing in raising J. and K. to be strong and vibrant people.
2. This gets better. An experience like this can be empowering and defining for J., and for K., given time and healing. This does not need to define her negatively.
3. Her diversity of friends can be a strength. People with different perspectives unconsciously show us different ways of looking at the world. That kind of wisdom does not come easily any other way. If there are obviously negative or harmful individuals associating with J., then of course they should not be tolerated, but otherwise, it's important to examine what we do not know before passing judgment. The worst case scenario (which I've seen in my professional work countless times) is the forced isolation of an individual, which only fed a stronger resentment and anger and catalyzed worse behavior later.
4. There does not need to be a reason. Drug-seeking behavior is a disease, not a character flaw. We do not need reasons to have a cold, flu, or cancer. There are things we can do to make us more vulnerable, like smoking or wearing wet clothes or whatever, but that's not a guarantee, nor is it really a reflection of our moral values. My point is that it's easy to cast judgment and say that someone is a bad person because they sought out drugs. But we are not bad people because we catch colds. At bottom, these are flaws in our neurological chemistry that we all have in subtly different ways, that manifest differently.
Some people drink. Some people have a temper. Some people get unstoppably curious. These are all examples of impulsive behavior that, when they act on it, trigger our brain chemistry to react with an adrenaline rush, and what is called, 'the dopamine cascade', where the chemicals and hormones in our system make us feel excited and energized, like the world is a fascinating place. In and of itself this is not a negative thing--it's how we experience all forms of pleasure. But when our system learns that the same physical actions result in the same pleasurable feelings consistently, our system starts prodding us to do those same physical actions over and over again. This is the basis of addiction as we currently understand it. The same chemical reactions happen in alcohol addiction as in drug addiction, pill-seeking, gambling addiction, sex addiction, etc., etc.
There is always hope. J. now has a precedent to reach out for help. That's something that the vast majority of individuals who have had similar experiences struggled to find and did not find. She has a strong support network. I have every confidence, from a professional as well as a personal perspective, that she will emerge from this stronger and healthier as a result.
Please know that I'm thinking of you all, and I'm willing to visit with J. and K. whenever possible.