It is so clear that you have no children or you have a sibling problems...your niece mother does not sound like a freak or a deviate...talk to her about having sex next to her child better yet just notify her of some noticeable behaviors that a 5 year old should not understand now..stripping that is television...you must see a deviate action against this child or the results of one...if not she is a normal child in an unconventional situation...break your heart... She playing one side against the other...bless the little one heart...

NOW to your brother... His daughter needs him...give him back his responsibly...stop allowing him to be an absent father...say no more to the all day visit with you and your mother ...your brother is using you...no good daddy will neglect his child.

You stop the hating and causing baby momma drama...more harsh words were expressed about her then your brother...you dismissed his responsibility

If I were a child and had fun at your house I would not want to leave...oh something else has comes to thought ...get both families together state you issues and develop an intervention plan...remember it takes a village to raise child...