As a new parent I am slowly beginning to comprehend the strange combination of responsibility and utter lack of control that being a parent involves. My heart goes out to you.

For starters - it's great that you brought your kids up well. And it's great that you've all survived this far. There's a lot of hope for your son and your daughter if they're in AA and sober. If they're still in their twenties it is so far from over yet and any parent who feels smug about their children in comparison to yours has their head so far up their arse that they're going to get a horrible shock one day when, inevitably, misfortune and sadness comes knocking at their door.

But I doubt that many are. It must be such an endless and awful temptation to go down the 'where did I go wrong?' path that it's inevitable you're going to think other people are going down that path when they think about you too. But anyone with any sense or compassion wouldn't do that. And for those who do - feel free to snap at them, confide in them, outright lie to them - whatever makes you feel better at the time.

My sister spent a long time wandering in the wilderness and she's just graduated with distinction from medicine at the age of 45. She's going to be a great doctor, partly due to the hard times she's been through and the compassion and wisdom that she has won. I know a whole lot more stories of this kind, including my own to some degree. There are so many stories of people who have been through addiction, rehab, mental illness and come out the other side better, stronger, people. And of course I know stories of those who haven't, too, and you must be terrified sometimes - but when you are think about how far your kids have come already.

Finally, and I know this might be controversial and/or useless to you - but can you give your children over to God? It can be really helpful to. If you have a God to give them over to then do it now! It will help you to love your kids better to free yourself of a false sense of responsibility for their problems. It might also help you release them from the 'it's all in the genes' narrative. Sure, genes have played a part, but it's by no means the whole story about them or their lives or their futures. They can make choices today that will change their whole trajectory and it's important for you all to affirm that.

Finally, their addictions and mental issues cannot be the whole story about them. It's no doubt the most painful attention grabbing part right now but they must also have their distinct and utterly individual gifts and beauty quite apart from that. They must have already done things and given things that you can point to and say 'I'm so glad I have been here to witness that.'

I think it's great that the LW has written in to Cary and is taking this seriously. Relationships are one of the most important things in life, and adolescence is a crucial time for learning about them and practising having them.

Incidentally, I am now no longer close with any of the people I was so close to during high school. I made my lasting friendships at uni. Which is to say to the LW - you won't necessarily stay friends with this person forever anyway, and that's fine. As someone else here has written, high school is a time of huge change and experimentation and you may find that you and your friend have become different people now from the ones who got along so well in seventh grade.

What I think would be bad is to feel that you had to stay close to this friend out of a sense of obligation or duty. It can be a real trap to fall into being 'the lucky one' - in your case with siblings and parents who aren't divorcing - and therefore somehow deserving of abuse. For starters, since when did having siblings automatically mean you don't get lonely and since when did being an only child mean you weren't having a great time? Cary is fantasising to think that in an unhappy family siblings somehow automatically ameliorate the harms. In many unhappy families siblings simply splinter, each holding on to their own particular means of survival and barely seeing the others as anything except fellow passengers on a doomed ship.

You will have hard times too - you're having one now - and you should expect your friends to care about that no matter what they're going through. Just as, by the same token, they should expect you to care about them. Not because of anything in particular about their situation but simply because you are friends.

So, forget about her parents and situation for a moment and ask yourself this: do you still care about her? If you do then hang in there. Keep telling her you don't like her behaviour and keep telling her you matter. If you don't still care though - and you did write that you just wish she'd go away - then end the friendship. Explain why if you can, and move on.