He wrote the script for Halley's Comet (2005) after his younger sister passed away of a rare form of cancer at age sixteen. The premise was of a young woman given six months to live and beating the odds to recover but everyone in her life still talks to her as if she was sick or dying which makes it difficult for her to move on and live. Kreisberg told Kevin Smith on his podcast, Fatman on Batman (Episode 103), that one day when his sister was being especially mean to him and he refused to retaliate, his father pulled him aside and explained that even though she was sick, she was still his bratty little sister and he should treat her like he would have before her diagnosis. He said that was the main inspiration for the show.
