The Profiteer(1974)

Original title: Il saprofita

In the city of Ostuni in Puglia, the mute seminarian Ercole is designated to be the driver and nurse of Parsifal, the paraplegic son in a rich and sanctimonious family of landowners. Ercole soon becomes the lover of his master's wife, the beautiful Baroness Clotilde. In a familial and social context where only money, sex and power count, everyone tries to take advantage of everyone, but the real saprophyte turns out to be Ercole.