There are two possible remedies to undue influence in creating estate plans.
The Texas Supreme Court recently had the opportunity to resolve an issue of influence in an estate plan. However, it chose against resolving the issue, according to the Wills, Trusts & Estates Prof Blog in "Unanswered Questions in Texas."
Instead of suing the estate in probate court, as is done in undue influence cases, in a tortious interference with inheritance rights, the person accused of improper influence is sued directly for the damages that he or she has caused.
Depending on the jurisdiction and the facts of the case, this is a cause of action that can be used instead of or in conjunction with an undue influence claim.
The Supreme Court in Texas was asked to determine whether the cause of action exists in Texas. The lower Texas' courts are split on the issue.
Instead of doing that, however, the court declined to do so. It determined that where undue influence exists, a constructive trust is a sufficient remedy for damages.
Reference: Wills, Trusts & Estates Prof Blog (June 2, 2017) "Unanswered Questions in Texas."