I'm going to call out my ex's lil sis for being rude and petty
How is she rude and petty?
Well she calls me a selfish bitch, a person who is not friendly, a bipolar person and a coward.
Even though it sounds like your ex's sister is very rude, you shouldn't call her out. It might be best just to disassociate from the family entirely.
It's fair she calls me out though, I've hurt her big sis with all my actions.
It sounds like you and your ex's family really don't get along. Do you really want to cause unnecessary drama by calling them out? How about just parting amicably and no longer getting involved for the sake of your health?