The Ruling Class (1972)

When the Earl of Gurney dies in a cross-dressing accident, his schizophrenic son, Jack, inherits the Gurney estate. Jack is not the average nobleman; he sings and dances across the estate and thinks he is Jesus reincarnated. Believing that Jack is mentally unfit to own the estate, the Gurney family plots to steal Jack's inheritance. As their outrageous schemes fail, the family strives to cure Jack of his bizarre behavior, with disastrous results.