How did Azucena’s death change Rolf?

When the speaker comments on Rolf's character traits before his meeting and interaction with Azucena, she describes him as having great determination and strength. She also comments on his unique ability to to emotionally isolate himself when he looks through the lens of a camera. However, this all changes when he decides to wade into the mud to comfort Azucena. He stays with her, helping her physically when he can, comforting her with conversation, and reassuring her that she will be rescued. However, on the second day, Rolf's memories of earlier years surface, particularly his memories of his own tortured past. Some of these recollections involve the horrors of the Holocaust. He remembers burying bodies at a concentration camp and seeing towering piles of corpses. Rolf also revisits his past childhood at the hands of an abusive father and his guilt at not doing more to protect his sweet retarded sister Katharina. Perhaps Rolf's inability to flee this tragic setting and save Acuzena rekindles old feelings of desperation, pain, and entrapment. Looking at Rolf on the screen, the speaker says that "something fundamental had changed in him." Rolf comes to accept Azucena's death, but the past's floodgates of painful memories are not so easily resolved. Rolf no longer takes pictures; he no longer writes or sings. The speaker knows that he is in the process of coming to terms with the pain and the death of the past, and she vows to wait for him to "complete the voyage" of remembrance and "return from [his] nightmares." This is what Rolf must endure to fully heal. For better or worse, Rolf will never be the same as before.

Rolf has spent almost every minute of the day with Azucena, doing everything he can to comfort and console the little girl as she remains stubbornly trapped in the aftermath of a gigantic mudslide. In the course of this tragedy, the TV documentary producer has identified himself with Azucena, so much so that, in his pain, he's forced to confront all the horrifying memories from his boyhood in Austria that he's managed to keep bottled up inside for so many years.
Rolf identifies with Azucena to such an extent that, by the time Azucena eventually passes away, a part of him dies with her. Rolf's never quite the same again. He intently studies the footage of Azucena trapped in the mud, asking himself over and over again if there was anything more he could've done to save her. His camera equipment lies unused in a cupboard; we get the impression that, after his traumatic experience with Azucena, he's stopped making documentaries altogether. It's notable too that Rolf no longer writes or sings. Instead, he spends long hours just staring blankly through the windows at the mountains.