Complex sentence: He shares his love of horses with Emilie, who reminds him of the daughter he left behind, and together they and her mother take care of Joey and Topthorn, who are being kept alive thanks to Joey being able to pull an ambulance for wounded soldiers.
Split into simpler sentences: He shares his love of horses with Emilie, who reminds him of the daughter he left behind. Together they and her mother take care of the horses Joey and Topthorn, which are being kept to pull an ambulance for wounded soldiers.