I know this is sad but what's the best way to do a book report?

That sound pretty good so far. I have got a good idea of what the book is about from what you have written. You don't have to summarize the whole book page by page - just give a detailed overview of what the book is about. Condense the significant parts into your summary, and I would conclude with what the theme of the book is about - it seems to be about an intense family relationship, touched by tragedy and abuse. The facade of a outwardly respectable family, and what goes on behind closed doors. I think you are doing quite well, stick with it. Good luck.