The Idlers of the Fertile Valley (1978)

At last, fortune has smiled upon a grizzled paterfamilias, who, after inheriting his older brother's immense property along with a discreet live-in maid, decides to move in his lavish mansion with his three grown-up sons. But there, in the heart of a secluded, enviable estate, overpowering sloth starts to get the best of the new tenants. And more and more--as the weeks turn into months, which turn into years--the four men embrace indolence from an impulse as sudden and profound as the inexplicable urge to defy life and sink into nothingness. Is there an escape from the deadly web of sweet, numbing languor?