My mom has been taking care of a child that's not hers and needs to know the writes of a biological aunt.

She can ask to adopt. Child services is suppose to find relatives when possible.

She will have to file a motion in family court to adopt the child, It will be easier if the bio parents (mother and father) will sign over for her to adopt

Who placed this child with your mom and where are the really mom and dad now? Aunt will likely be considered foster kin ahead of your mom.

Who placed this child with your mom and where are the really mom and dad now? Aunt will likely be considered foster kin ahead of your mom.

I think her mom is the aunt

Nohelp, it's a guess at this point. After rereading the post it sure isn't clear is it? We need more info and details about mom and dad and how placement came to be but you could be right. Thanks, Bob