The original book has Forrest hanging out with an ape and going into space as well. It is appalling bad and almost unreadable. I am still amazed that anyone was able to translate it into an Academy Award winning film (despite many opinions, I am still a huge fan of the movie and still think it is a brilliant touchstone).
What I am saying is that the book(s) and the movie aren’t that closely related. I have read the books and seen the movie dozens of times. At least in the movie, she died of AIDS complications. That is made abundantly clear without being blatantly stated. It really doesn’t matter what the book says because the screenwriters completely rewrote the entire story to be a montage of late 20th century history as seen through a retards eyes.