Complex sentence: Ayla had been sent for a stay with her father, Justin DiPietro, by her mother and primary caretaker, Trista Reynolds while Reynolds attended a substance abuse recovery program.
Split into simpler sentences: Ayla had been sent for a stay with her father, Justin DiPietro, by her mother and primary caretaker, Trista Reynolds. Trista had sent Ayla to stay with Justin while Reynolds attended a substance abuse recovery program.