Translating & Rewriting

I'm supposed to translate this chapter of a book for an International Organization. I was warned about the 'weirdness' of its content. Let's just say it's not up to standard for a publish book nor a scientific report even though it was written by a Ph.D. (I need to know where did he get his Ph.D. from) and was presented at a meeting somewhere.

At the moment I question myself: am I translating or rewriting the chapter? It's becoming more and more the latter, because some sentences are so jumbled up I cant even be sure what the author is trying to say. And I thought Bahasa Indonesia is my mother tongue! I guess it is not the authors' mother tongue.

BTW, there is this Indonesian saying 'tak kenal maka tak sayang' literally means 'if you dont know, you dont care', I have this feeling there's an English equivalent proverb for that but I cant recall the wording. Can anyone help? Thanks