PROB §21380: (a) A provision of an instrument making a donative transfer to any of the following persons is presumed to be the product of fraud or undue influence: (1) The person who drafted the instrument.

(a) A provision of an instrument making a donative transfer to any of the following persons is presumed to be the product of fraud or undue influence: (1) The person who drafted the instrument. (2) A person who transcribed the instrument or caused it to be transcribed and who was in a fiduciary relationship with the transferor when the instrument was transcribed. (3) A care custodian of a transferor who is a dependent adult, but only if the instrument was executed during the period in which the care custodian provided services to the transferor, or within 90 days before or after that period. (4) A care custodian who commenced a marriage, cohabitation, or domestic partnership with a transferor who is a dependent adult while providing services to that dependent adult, or within 90 days after those services were last provided to the dependent adult, if the donative transfer occurred, or the instrument was executed, less than six months after the marriage, cohabitation, or domestic partnership commenced. (5) A person who is related by blood or affinity, within the third degree, to any person described in paragraphs (1) to (3), inclusive. (6) A cohabitant or employee of any person described in paragraphs (1) to (3), inclusive. (7) A partner, shareholder, or employee of a law firm in which a person described in paragraph (1) or (2) has an ownership interest. (b) The presumption created by this section is a presumption affecting the burden of proof. The presumption may be rebutted by proving, by clear and convincing evidence, that the donative transfer was not the product of fraud or undue influence. (c) Notwithstanding subdivision (b), with respect to a donative transfer to the person who drafted the donative instrument, or to a person who is related to, or associated with, the drafter as described in paragraph (5), (6), or (7) of subdivision (a), the presumption created by this section is conclusive. (d) If a beneficiary is unsuccessful in rebutting the presumption, the beneficiary shall bear all costs of the proceeding, including reasonable attorney’s fees.