I'm truly sorry to hear about your sister. Drugs are certainly not going to help her case, but she sounds lost and lonely. I don't doubt your parents gave you all a nice upbringing & worked hard for you, but there's more to parenting than that. BEING there, listening, showing (to receive) respect, talking, not being judgemental and commanding good manners and behaviour.These little things help children to expand into good adults, but maybe your poor sister has some form of illness, & it might be best if someone more responsible looked after her children. She had them very young. She needs help.