Jean Clitheroe, 76, left almost her entire estate to her son when she died in 2017
Jean, of Essex, cut 'shopaholic daughter' out, saying she would 'fritter it away'
Judge ruled Jean died intestate because she was suffering from 'delusions'
Son John challenged ruling in ground-breaking test case which sought to scrap 150-year-old inheritance law and claim it no longer applied in modern society
High Court judge disagreed and threw out John's argument, offering the siblings a chance to settle the matter out of court to avoid further costly proceedings