Hazel and Van Houten's final interactions are slightly altered in the movie. In the book, Van Houten scares Hazel from the backseat of her car after Isaac tells her Gus is writing a sequel to An Imperial Affliction for her. After Hazel tells Van Houten to get sober and write another book, he goes home to Amsterdam and never speaks to her again. Instead, as Hazel becomes obsessed with finding Gus's writing, she realizes four pages of his journal are missing, which he had sent to Van Houten. This later leads Lidewij to force Van Houten to read the eulogy, and then she sends it back to Hazel.
In the movie, Van Houten shows up in Hazel's car after the funeral, and he tries to give her a letter without telling her what it is. He lets her know that he corresponded with Augustus, but not the details of their exchanges. She kicks him out of the car without any nice parting words about getting sober, and then later, Isaac tells her about the eulogy (instead of the Imperial Affliction sequel). She then finds Gus's crumpled-up letter she had thrown in her backseat and reads it.