Hi,
I hope that you don't mind me popping in to comment. I have a dear friend who's parents are in the same situation. Child services was called into their son's home (both son and wife are addicts), the grandparents were very involved and given temp custody.
They are currently in a lengthy legal battle trying to get permanent custody of the grandkids. This includes going to court, drug testing of the parents etc etc. It has been very very difficult on them, but they want to raise those kids in a safe environment.
All I can say to you is go with your heart. Pray on it. It will be difficult. Sounds like it's not a good place for those kids..
Karen