A trustee shall not be liable to a beneficiary for a breach of trust committed by a co-trustee, unless he:
(1) Participates in a breach of trust committed by his co-trustee;
(2) Delegates improperly the administration of the trust to his co-trustee;
(3) Conceals, approves, or acquiesces in a breach of trust committed by his co-trustee;
(4) Enables his co-trustee to commit a breach of trust by his failure to exercise reasonable care in the administration of the trust; or
(5) Neglects to take proper steps to compel his co-trustee to redress a breach of trust.