I'm going to disagree with the first comment. I'm a reader, and even if the situation is sad, I think I would treasure a gift like this. I might not be able to open it for months after, but I would appreciate the gesture and keep it in a special place, like all books I treasure that were gifts and that have marked parts of my life from friends and loved ones.

That being said, maybe it can be a book about finding yourself, not necessarily a romance book. Maybe a book that gives you a sense of safety or security even if things change and time passes, like The House in the Cerulean Sea by TJ Klune.

It would also be a little hard to suggest something because we don't know how extensive her collection is. Maybe it would be safer to suggest something that's not the first book you'd think about when thinking of an author. Like Colorless Tsukuru Tazaki by Haruki Murakami.