Get custody of my mothers grandchildren from their unstable abusive homes.

My sister trusted a woman to take care of her 2 kids because she knew she was unstable to. At first, things were fine but then bad things started to happen. The woman would hurt my little niece. We knew this because each time she came over, she would say how the woman "would hurt her" and sometimes "not feed her". Of course, we didn't automatically believe her becaus she's 4 but we began to see the bruises and notice her fear each time we drove her back to the woman's house. We've tried to take legal action and gain custody of the kids but we lost the battle. Time skip to a year later and we found out my niece is in the hospital from severe burns for a whole month. We didn't even find out from the woman but instead from the CPS. Please help us gain custody of them by signing this petition.