Sifting the delusional from the merely mistaken

Contentious probate practitioners are familiar with the difficult discussions with disappointed, would-be beneficiaries ("DB") in which the stated reasons for DB's exclusion given by the testator ("T") to the drafting solicitor are dissected. Typically, these explanations might include things the DB has apparently done (disparaged T, sponged off T, stolen from T), not done (provided care, visited T sufficiently) or received from T during their lifetime (enough, more than others) which the DB asserts are demonstrably false.