Since John is older and has more assets than his new wife, they created a Revocable Joint Trust that will become two trusts upon the death of the first spouse. While they are both alive, they may make any changes they want to the trust, but once one of them becomes deceased or incapacitated, a disclaimed amount of assets will be transferred to the Irrevocable Bypass Trust. Since this trust is irrevocable, the terms of the distributions, trustee, and beneficiaries cannot be changed. The remaining assets will be placed into the Marital Trust, which can be changed or amended by the surviving spouse. Upon the death of the second spouse, the assets of both trusts will be split according to their terms.
The trust splits into two:
Marital / "A" Trust
Bypass / "B" Trust (funded with the estate tax limit/disclaimed amount)
Assets from both trusts are distributed to the children according to their terms:
Child 3 (child of John) — receives portion of Marital Trust and Bypass Trust