What's sad is how these tragedies are prolonged because the parents of the addicts are always willing to give them another chance. Having a similar problem in our family.
My mother-in-law has been scammed out of nearly all her valuables and money by my pill-addicted sister-in-law, my niece neglected to the point where her baby teeth were rotting into her gums and she almost had to repeat 2nd grade from missing so much school. Last year, most of the Christmas gifts that we bought for her were returned for cash.
When child services put her in my MIL's custody, she refused to file for legal guardianship. After a couple of months and many promises from SIL, my niece was back with her addict mother. After missing 2 weeks straight of school, her aunts and uncles finally stepped in and went to court. We now have joint legal guardianship and SIL is in long-term rehab, though we are very skeptical that it is making any difference. SIL lives in a la-la land where she's a great mom, and sadly, MIL will never lose hope that this could be true.
I really hope there is someone else in this family willing to emotionally detach from the mother in order to take care of her children. The grandparents unfortunately don't seem to have the will power or foresight to adequately assess the reality of this situation.