Short answer. Yes. Rule 76, Section 9 lets a court disallow a will if it was procured by undue and improper pressure and influence, whether from the beneficiary himself or from someone else acting for that beneficiary's benefit. Ordinary persuasion is not enough — the pressure has to be improper and has to have driven the testator's decision.
What the law says
If it was procured by undue and improper pressure and influence, on the part of the beneficiary, or of some other person for his benefit
Rule 76, Section 9 — Grounds for disallowing will. Read the full provision →
The ground itself
Section 9 states that a will shall be disallowed if it was procured by undue and improper pressure and influence, on the part of the beneficiary, or of some other person for his benefit. The phrase does the real work: the influence has to be both undue and improper, meaning it went beyond what is ordinarily accepted and instead overrode the testator's own judgment about how to dispose of his property. A will that simply favors one relative over another is not, by itself, evidence of undue influence.
Reaching beyond the beneficiary named in the will
The ground is not limited to the beneficiary personally applying the pressure. It also covers pressure or influence exerted by some other person for his benefit — someone acting on the beneficiary's behalf, or to the beneficiary's advantage, even without being named in the will themselves. This closes an obvious gap: a beneficiary cannot avoid the ground simply by having a relative, caretaker, or intermediary do the pressuring instead of doing it personally.
What separates undue influence from ordinary persuasion
Families routinely try to persuade an elderly relative about how to leave property, and affection, care, and closeness legitimately shape a testator's choices. What this ground targets is different in kind: pressure and influence that are undue and improper — pressing on a testator's fears, dependency, or weakened state to substitute someone else's wishes for his own, rather than simply making a case for a particular outcome. The line is not always obvious in a given case, which is exactly why this ground exists as something a court has to weigh rather than something that is presumed from a lopsided will.
One of several related grounds
Undue influence sits alongside four other grounds in the same section: defective execution, the testator's insanity or incapacity, duress or fear, and a signature procured by fraud or trick without the testator intending the document to be his will. These grounds are not the same thing — duress typically involves threats or fear forcing the testator's hand, while undue influence can operate more gradually, through sustained pressure on someone in a dependent or weakened position, without any single threatening act.