Confused on FAFSA and CSS Profile, help?!

I’m really confused on the CSS Profile and the FAFSA. My mother is here illegally and I have no idea where my dad is at all and neither does she. We currently live with my sister who is legal and she is the one who buys us things we need and etc. My mom doesn’t pay taxes since she doesn’t work so my sister claims me and my brother on the tax returns. My question is since my sister is the one claiming me on her taxes would I just put her information on FAFSA? And since I have no contact with my dad how am I supposed to get my nonresidential profile filled out by him?

You can’t use your sister.

You need to use your actual parent…unless your parent has given legal guardianship to your sister.

Someone else will have to clarify whether your sister can actually claim you as dependents…and what the implications of your mom’s undocumented status means in terms of financial aid.