Complex sentence: However, a fight breaks out between them, when Kym asks Abby why she left Ethan in her care on the night of his death despite knowing that she was often on drugs, suggesting that Ethan would have been better off in Rachel's care.
Split into simpler sentences: However, a fight breaks out between them, when Kym asks Abby why she left Ethan in her care on the night of his death despite knowing that she was often on drugs. She suggests that Ethan would have been better off in Rachel's care.