<human>: Look, I'm going to make this as brief as possible, because a lot of shit has gone down recently between my sister and parents. 

Firstly, she was supposed to get married in April. She got nervous around november/december, and decided that she didnt want to be with her fiance. So they called off the wedding. My parents were furious as they invested a good amount of money in the wedding. They got over it, she went 4 months and now she realizes she made a mistake, she wants to be with her fiance, and they are now seeing each other again. 

So now she drops this BOMB on me and my parents. She's pregnant (With the fiance) and my parents are flipping a shit. My dad is throwing her out of the house, and saying he never wants to see her again. 
In my opinion they are being very selfish by saying "they" are hurt. Meanwhile my sister is happy. 

What can I say to my parents to get them to see the big picture. Theres a BABY entering the family in 7 months, this needs to be a HAPPY time!!!

Thanks ALL!

Can you give me the gist of the text in a nutshell?
<bot>: Sister is having a baby out of wedlock, parents are taking it really hard, and dont want to see her ever again.