Question: does the boy die in the space between us

Answer: No, Before they begin their journey, they make a detour to Las Vegas. Gardner's nose starts to bleed again and he collapses and is taken to a hospital. After seeing the carbon tubes in his bones on the results of an X-ray at the hospital, Tulsa tells Gardner she now believes he was born on Mars, but plans to leave him in the hospital, before foster care can come, as he is too sick to continue their journey. Gardner reveals that he knows he won't last on Earth anymore and all he wants is to meet his father before he dies. Tulsa gives in and helps him escape. They steal a car and drive to the beach house. There, they meet the man from the video, who reveals that he is not Sarah Elliot's husband, but her own brother. However, he thinks that the two are lying to him. Gardner runs down to the sea, where he tells Tulsa that this is where he wants to die. He collapses. Tulsa tries frantically to drag him to the shore, but he is too heavy for her. Nathaniel and Kendra arrive just in time to save him. After Nathaniel performs CPR on him, Gardner asks him about his mother Sarah and reveals that he knows that Nathaniel is his real father. Nathaniel, Kendra and Tulsa rush Gardner to a Dream Chaser. They plan to launch into the stratosphere to stabilize him. When that proves to not be enough, a desperate Nathaniel takes control and launches into outer space. Free of Earth's gravity, Gardner is revived.