(a) After the death of both settlors, all property held by the trustee of the qualified spousal trust shall be distributed as directed by the then-current terms of the governing instrument of the qualified spousal trust.
(b) After the death of the first settlor, if immediately before his or her death the predeceased settlor's interest in the qualified spousal trust was held in a separate share, the property held in the predeceased settlor's separate share may pass into an irrevocable trust for the benefit of the surviving settlor as provided by the terms of the governing instrument, including without limitation a spendthrift provision.