Complex sentence: Massoud drugs Nadereh's tea with a lethal dose of medication, killing her quickly without telling her of their son's death, then dons his old military uniform, tapes a plastic dust cover around his head, and asphyxiates himself beside Nadereh's body.
Split into simpler sentences: Massoud drugs Nadereh's tea with a lethal dose of medication. He then dons his old military uniform, tapes a plastic dust cover around his head, and asphyxiates himself beside Nadereh's body.