Is AUTHOR wrong in the post ? POST : My dad comes from a very long line of sexist idiots.  If a girl is born in the family, you have nothing to do with them.  In short, girls are only good for reproduction and cleaning.  This means he can't stand me.

Now aside from his distaste of me, he has been a complete douche of a person let alone a dad.  He cheated on my mom with my brother's and my babysitter.  A woman with a full grown 'stache.  Evidently she was psycho, he and her kept breaking up and he would end up with my mom again.  Then he would go back to the 'stache.  Rinse and repeat.  He finally left Groucho and went back to my mom one last time before cheating on her with his new wife.  This woman made Satan look like a cuddly teddy bear.  

Now in this time, my mom has moved on and remarried.  Unfortunately, her husband eventually passed and she was a widower for some time.  Then my dad's wife passed.  And the two thought, let's get back together.  A true nightmare.  They have been back together for a couple of years now.  When I say together, I mean he moved in.  They share a bed but have NOT remarried.  He couldn't afford to live on his own.  Lucky me, I see him too often.  They are somewhat happy.  My dad has not changed.  Still a jerk.  Still doesn't like me and he's very controlling to my mom.  Which was made worse when she was diagnosed with stage 3 bone cancer.  He thinks he knows everything.  Even if it isn't what my mom should be doing for her health, he says do it.  I try to help at their house but he refuses to let me.  Currently, my mom is in the hospital in very bad shape.  She asked me to get things from her home.  Old dad wouldn't let me.  The icing on the cake, he sent my mom a text saying he prefers my brother to me.  Yes, he did this while she has cancer and in a hospital.  Fantastic guy.  She cried, of course.  

My question; since my jerk of a father wants nothing to do with me and apparently loves my brother more, WIBTA if I ask my brother what is my dad's problem?  I feel like I am not going to be able to care properly for my mom because I am being denied that and he is going to send her to her grave before she has had a chance to fight.

TL;DR my "dad" hates girls and won't let me do what is right to take care of my mom, whom he has treated like garbage over the years because he prefers my brother to me.