My sister lives w/ my step father. My mom HAD to leave the home. My sister is 13 and decided to stay w/ father. I don't think he can take care of my sister.. he can't hardly take care of his self. He receives a disability check for his self and my sister gets one also until she is 18. He BLOWS all of his and her money. Now he is asking for child support from my mom?? How do we fight for this?