In the final moments of the “9-1-1” Season 9 finale, it was revealed that Buck has taken in preschooler Theo and will be fostering him after the unexpected car-crash death of Theo’s parents (who were Buck’s good friends).
During the final moments of the Thursday, May 7, episode, titled “Hearts and Flowers,” it was revealed that Buck signed paperwork making him the legal guardian of 4-year-old Theo after his parents, who utilized Buck as a sperm donor, both died in a tragic accident.