Complex sentence: According to author, Szaniawska ("née " Szatkowska) starved and abused his physically, fed him dissolved plaster (as"medicine"), and isolated him entirely from the world, until his death in 1970.
Split into simpler sentences: According to author, Szaniawska ("née" Szatkowska) used to beat her husband and feed him plaster. She isolated him entirely from the world, until his death in 1970.