At the park one day, Jenny tells Forrest that she's sick with some kind of virus that the doctors don't understand and can't fix.
Based on the fact that this is taking place in the '80s and it's a virus doctors don't understand and that Jenny has probably not been practicing safe sex or hygienic needle usage, we can reasonably guess that Jenny has AIDS.
Forrest says he'll take care of Jenny, and Jenny ask him to marry her back in Greenbow, Alabama.
Guess who shows up at the wedding with a fancy new pair of metal legs? That's right, it's Lt. Dan, and he's there with his fiancée, Susan. It looks like things have worked out really well for Lt. Dan.
One day, Forrest brings breakfast in bed to Jenny, who looks like she's getting worse. She asks Forrest if he was scared in Vietnam. He just tells her that sometimes it was nice when the stars came out. Then, he thinks of all of the times he looked at the sky and thought of Jenny.
Jenny dies on a Saturday morning, and Forrest stands at her grave, finishing his story. He has her old house bulldozed because she hated it so much.
Forrest tells Jenny's grave that their son is doing just fine and that he's taking good care of him.
Forrest Jr. has written a letter for his mom, but he doesn't want his dad to read it. Forrest just leaves the letter at Jenny's grave.
Forrest says he's not sure if each person has a destiny or if they're just floating around randomly (like that feather). Maybe it's both at the same time?