Waterman,
I have a couple of thoughts.
First, could you start making some time for the kids? Do you have the extra time? It sounds like you are already an uncle of sorts. Just a thought that maybe you could help to enrich their lives, cause you sure can't fix their parents.
Second, be very careful. Do not forget that your sobriety comes first. You can not be the example that they need to see if you relapse. Remain focused on yourself and your recovery, they will see it, even if it does not seem like it right now. And you are not strong enough in your recovery yet to go saving anybody. take care of you!!
And if you can, help out the kids where you can.
Best of luck to all of you.