I need help with my niece please?

ok my sil took my 5yr niece to another state away from all of us including my brother. he couldnt get any help until he gets a divorce anyway they came back to this state and my sil mom gave my niece to my brother and while he had her she told my mom that her mom and her b/f did things to her well they told childrens svs ect but my sil came and took my niece again and ran with her back to the other state, they arrested her and her b/f for it but instead of calling family they put my niece in foster care in that other state she just turned 6 and my mom and brother keep going to see her as often as they can its a long drive and they are trying to get custody of her back (im not sure why that hasnt happened yet) anyway the big problem is this my niece was potty broke of course but when my mom went to see her this week she had her book bag and she usually cant wait to give it to my mom so she can look at her school work this time she didnt want my mom to see the bag (cont in additional)