<human>: -throwaway account-

So my parents got divorced when I was around 2 and my sister, 5.  Soon after, my father took us on a trip across Europe to visit his family and friends.
His side of the story:
I had a bad asthma attack and the doctors wouldn't let me fly on a plane for a month (he has paperwork from some doctors, I can ask him to send them to me if you want-they are in Polish). He decided to take me to my mother's family in Portugal, though he didn't speak the language and confused his parents-in-law and they called up my mom and said some bad things about my father.
My mom's side of the story:
My father was kidnapping us and wanted to keep us away from her because he didn't think she could raise us properly (father claims to have caught her cheating on him, thus the divorce).

Soon thereafter my mother had to illegally travel to Poland to literally snatch my sister out of daycare and later acquired me from my father after some court proceedings within the US.

Ever since this incident, my sister refuses to speak to or communicate with our father.  She has taken my mother's side on every aspect of this and whenever I bring it up, she says "You were too young, you didn't experience it as I did and don't understand."  Maybe my father did something to her he won't admit?

Her wedding is coming up next year and she has requested I not tell our father about it.  I will be taking up a job with my father in a couple of years and I fear this will defer my relationship with my mother (though she is far more reasonable these days).

Am I being a pestering drama inducing brother for still being bothered by this?  If not, is there anything I can do to somehow ease my sister into opening up a dialog with my father (I haven't asked her in years, but I used to bug her a lot about it and she would get angry instantly and shut me out)?

Can you give me the gist of the text in a nutshell?
<bot>: My father took me and my sister on a trip after divorcing our mother, since then, my sister won't talk to him.