I haven’t read the book actually. I grabbed this from the plot summary:

“ The "Bug War" has changed from minor incidents to a full-scale war during Rico's training. An Arachnid attack that annihilates the city of Buenos Aires alerts civilians to the situation; Rico's mother is killed in the attack.”

I’ll read it but right now I remain suspicious

Neither did Verhoeven, he apparently only read a couple chapters and had an assistant summarize the rest (https://www.looper.com/358395/the-real-reason-the-starship-t...). So I wouldn't assume that the movie strictly adheres to the events laid out in the book.