Private Nurse (1978)

Private nurse Ange seems to make a nice living from killing off old geezers, make that abundantly wealthy old geezers, at the request of their invariably much younger second or third wives. Following her latest 'success', she's off to the French countryside to care for crusty ailing millionaire Charles who makes life miserable for all around him, none more than his nympho wife Carole and his estranged bisexual son, Olivier. While she gradually smothers the old man with kindness, taking time off to seduce each family member separately in a series of creative encounters, his nearest and dearest barely bother to conceal their outright hatred for their family man as well as each other.