My Nieces and Nephews are in trouble help me?

I live in Nixon, Texas i have 6 nieces and nephews they are with my sister now, they were with their grandma until the daughter brought problems the ages of them from youngest to oldest is 1, almost 3, 7, 9, 10, and 14. We have done anything we can do but no matter what we do she LIES her way out of it we called cps, cops and nothings happens she lies her way out of it! She is not all there she is crazy I love my sister but my nieces and nephews are scared of her and nothing ever happens to her i need a way to get them back home here wit there grandma PLEASE SOMEONE GIVE ADVICE!!!!! if you have any questions or need more detail please just email me at fallenangel_1856@yahoo.com please help me i need it quick before one of the kids are hurt one is so scared he says he will kill his mom please help we need it bad!!! and we don't have money for a lawyer so what do we do??