Im Pentecosal my friend backslid..?

Lets say her name is "Natalie". We were best friends since we were born (literally) she lived with her Pentecostal grandparents since her parents were, well, bad parents. Its hard for me to explain how much she meant to me. But her grandma died, and according to custody laws, she had to move in with her horrible mom. Its been four years and now, Natale wont trust me. she is backsliden, if you knew her mom you'd understand. at first she was so sad, now shes brain washed. i dont know what people did to her, but she wont even tell me were shes going if shes in the car. shee thinks im just trying to "change her' she says "i just want to be me". yeah. well.she needs� to come back to God. she lives in a horrible neighborhood, and shes been expelled? she really wont tell me why! i miss my friend. i want her out of her moms custody, but no way will her mom allow that. her aunts kids are also my really good friends, and their saved, oh how i wish she could live with them. Im 14 and so id she, i dont really know how to deal with backsliders expertly, any godly advise??