There are additional fiduciary duties in play when there are cotrustees of a trust.
If cotrustees are serving, the default rule is that they act by a majority decision. Section 456.7-703.1, RSMo. A cotrustee is under an obligation to participate in the performance of a trustee’s function — unless the trustee is absent, ill, legally disqualified, temporarily incapacitated or the trustee has delegated his function or authority to another trustee.
Further, a cotrustee is under obligations to prevent a cotrustee from committing a serious of breach of trust and to compel a cotrustee to redress a serious breach of trust. “A cotrustee does not escape liability by failure to participate in the administration of the trust.” Ramsey v. Boatmen’s First Nat. Bank, 914 S.W.2d 384, 388 (Mo. Ct. App. 1996). A cotrustee may be responsible for breaches of trust of his cotrustee to which he consented or which by his own negligence he made possible for his cotrustee to commit. Id.
As an exception to this rule, a dissenting cotrustee who, among other things, notifies the other cotrustee(s) of the dissent at or before the time of the action may escape liability.