The Clouds true story reveals that Zach had osteosarcoma, the most common type of bone cancer. Like other cancers, its deadliness depends on whether it's a high-grade or low-grade tumor, how responsive it is to chemotherapy, and whether the disease has spread. Osteosarcoma most commonly affects males under the age of 25, and as with Zach, it often begins at the end of long bones. Zach's developed in his hip. -SarcomaHelp.org

Yes. The movie is based on the book Clouds: A Memoir written by Laura Sobiech, Zach's mom, who is portrayed by Neve Campbell. She began writing the book three weeks after Zach passed away, completing it 12 weeks later. Laura had started a blog several years earlier after Zach was diagnosed, which she mainly used to keep family and friends updated on Zach's battle with osteosarcoma. When she learned Zach's condition was terminal, the blog turned into a place to log precious memories that she could keep close after he was gone. She would later use the blog as the basis for the memoir. Laura decided to write the book after a friend's agent, who had been following her blog, asked her if she would want to turn it into a book.

Zach met his girlfriend Amy Adamle through his best friend and longtime music-making partner Sammy Brown. Zach and Amy got to know each other during their junior year. "We both knew we liked each other, so by the end of junior year we started dating," Amy recalled, "and that’s when we found out he was terminal, so our relationship was pretty serious pretty quickly. We had to be really open with each other, and we had to talk about things that no one really has to talk about when you're 17." -ChildrensCancer.org

No. The breakup never happened in real life. It was done for dramatic effect to give Zach's character motivation and to move the story along.

Yes. The true story behind Clouds on Disney+ confirms that Amy Adamle (portrayed by Madison Iseman) and Zach started dating shortly after he found out his cancer was terminal. Amy talked it over with her mom, and her mom asked her, "Would you still date him if he didn't have cancer?" Amy said yes. Zach and Amy continued dating throughout their senior year of high school. Zach even took Amy to prom not long before his death in May 2013.

Both Amy and his best friend Sammy met their onscreen counterparts and visited the Clouds movie set. Amy shared some of the letters that she and Zach wrote to each other with Madison Iseman and Fin Argus, who play Amy and Zach in the movie. -ChildrensCancer.org

No. From what we can tell, Mr. Weaver (Lil Rel Howery) is a fictional character. There is no Mr. Weaver in Laura Sobiech's memoir. He seems to have been very loosely inspired by Dan Seeman, the general manager of the local radio station who was instrumental in making things happen for Zach, including getting him a studio and a group of professional musicians to help him record "Clouds."

Yes. Like in the Clouds movie, Zach had learned to play guitar when he was little and he wrote the songs as a way to say goodbye to his family and friends. This is well-known and is clearly evident in the lyrics to his hit song "Clouds."

Yes. According to Zach's friend Mitch Kluesner, actress Summer Howell did an accurate job of portraying Zach's younger sister Grace, even down to the amount Grace rolled her eyes in real life.

Yes. Though it's not depicted in the movie, the Zach Sobiech true story confirms that he could have had his left leg amputated, including his pelvis bone, but decided against it. Zach and his family felt that his quality of life was more important. If he had gone through with the amputation, it may have removed the cancer in that region, but he wouldn't have been able to sit up for several months. By that point, the cancer had spread to his lungs. The chemotherapy had largely stopped working. Zach decided to stop chemo, opting to live the remaining days of his life to the fullest.

Yes. As a car enthusiast, Zach had reasoned that a Nissan GTR would be an affordable high-end sports car that might be within his reach someday. The Clouds true story confirms that his family indeed surprised him by getting him a GTR on loan to drive for a week. However, his dad didn't get the car without involving his mother. In reality, it was actually the director of the documentary (and later the Disney+ movie), Justin Baldoni, who managed to have Nissan ship the car up from Nashville for a week.

Yes. The trip to France indeed happened in real life, but it took place in March 2012, not during Zach's senior year. The trip was also prior to Zach finding out his cancer was terminal, which he learned two months later on May 31, 2012. They spent three days in Rome first, before spending two days in the town of Lourdes, the portion of the trip depicted in the movie. It's true that they dipped into the healing waters at the baths, which was the primary purpose of the trip. In real life, a total of eleven people went on the trip, including family and friends. After Lourdes, they spent a few days in Paris.

No. The actual concert took place at the Varsity Theater in Minneapolis on February 16, 2013. It was a fundraiser for the Zach Sobiech Osteosarcoma Fund. His mom did ask him if it might be too much for him to perform, but his condition at that point wasn't as dire as it's portrayed to be in the movie. In the film, the concert happens several months later. Zach finished his entire set at the concert. He never stopped partway through "Clouds," prompting the crowd to jump in and finish it for him. That was done in the movie for dramatic effect. At most, his mom noticed his voice sounded a little raspy, but she reasoned it might be from talking so much before the show. Also, Zach didn't perform the song with Sammy. He performed "Clouds" with Vicci Martinez, who had been recently featured on NBC's The Voice. At the end of the concert, confetti fell from the rafters and Zach held open his arms to the crowd and mouthed, "Thank you."

Unlike the movie, the concert wasn't a combined prom event. The real Zach Sobiech attended prom several months later in early May when his condition was significantly worse. They were unsure if he'd make it and how long he could stay, but he and Amy were there for several hours and had a great time.

No. Zach didn't kneel down in the street underneath a theater marquee with the question, "Will you go to prom with me?" displayed above him. In real life, Zach Sobiech asked his girlfriend Amy Adamle to prom while they were on air doing a radio station interview.

Zach Sobiech's mother, Laura, says it was the family's faith in God that got them through the grief. "I was certain that I was not going to survive losing a child, but I survived it, not because of anything special about me, but by God's grace." Laura speaks about her Catholic faith in her book Clouds: A Memoir.

Zach himself credited his older sister with helping him stay close to his faith. "I want to be remembered as a kid who went down fighting, and didn't really lose," Zach said.

Yes. 70 of Zach's family and friends were extras in mainly two of the movie's scenes. To appear in the film, they traveled from Minnesota to Montreal, Canada where the movie was shot. The scenes include the Jason Mraz concert and the prom scene. The cellist in the prom scene is played by Zach's real-life friend Mitch, who also appears in a classroom scene sitting behind Zach (Fin Argus). Zach's younger sister, Grace, plays a high-school student towards the beginning of the movie. His former girlfriend, Amy Adamle, is in a dance studio scene next to her onscreen counterpart played by Madison Iseman. We identify all of the cameos in our video Clouds Cameos: Zach's Family and Friends in the Movie.

Further explore the Zach Sobiech true story by watching his My Last Days documentary episode. Also, check out some of his music videos.