How do you explain drama in the family to a child with ASD

To set the background for my topic today of "How do you explain drama in the family to a child with ASD."  I have to give you a little background into my childhood.  Honestly, I wish I could say that my childhood was normal and that we were a functional family, well that is so not the case.  Don't get me wrong, my mother is one of the most loving and caring mothers in the world, but my father, he was a monster.  I grew up with my two half sisters and my half brother, I was the youngest and the only child from my mother and father's marriage.  My siblings are all much older than me (7, 8 and 12 years older), we did not grow up happily, unfortunately we were victims of abuse by my father.  If you try to talk to my sisters about this they refuse to speak of it like it is the dirty secret, if they read this they would be humiliated, but I am not.  I am a survivor of severe mental, physical and sexual abuse by my father.  I have grown and although it took me a very long time, I have learned to accept and deal with what has happened to me, and I have educated my daughter so that NOTHING like that will happen to her. 

Needless to say my oldest sister did not deal with it as well, she has gone from abusive relationship to abusive relationship.  Currently our mother lives with her and her current abusive boyfriend, a very unhealthy living environment.  I truly love my sister, however she is brainwashed by this abusive monster and will not realize that what she thinks is love is far from it.  On Monday night this came full swing into my life, she called begging me for help to get him out and that he was threatening her, this night was a nightmare.  By the early the next morning, my sister was in the ER for attempted suicide, the monster was detained for assault and battery against me and my fiance, and my mother was in absolute turmoil. 

My question to you is, how do you explain that to your child that his favorite aunt has disowned him and his family and chosen an abusive monster instead?  How do you explain the tears you are crying as you worry for your sister and mother's safety to your child?  I am at a loss and I have no answers for him, I just don't know what to do.