Prayers for those kids - they are always the collateral damage of addiction.
Encouragement to keep trying to serve the truth. It may hurt a lot to not see your grand kids, and the bigger issue is how to do whatever you can to change what you can.
For me, I am never shy about calling social workers, school counselors, doctors (if I know who they are) and any other authority that may have even the slightest influence. I have called judges and my addicts P.O. and even the prosecuting attorney in her drug cases. It has helped me channel my energy into something positive. I try to be very calm and logical and understand their position so I don't come off like a crackpot - but I continue to look for the things I can influence. I agree with hopeful4 - don't stop serving the truth.
And while it may not offer too much consolation - I have found that prayer - mine and anyone I can get to pray for me - helps in amazing ways. I find answers, I calm myself so I think of new avenues to explore and it helps me trust my (and my addict's) Higher Power. It gives me the peace to let go and let God so that I can go the long haul.
Prayers for those kids and for strength for you!