A person has a legal Revocable Trust that names her Son as both Executor and the beneficiary of the Trust at her death.
After her death the Executor never takes the steps to legally distribute the funds and terminate the trust.

The named beneficiary of the trust now draws up a will (prior to the trust being probated legally) that names beneficiaries of property and funds that are still in the trust. The named beneficiary of the Trust now dies prior to the Trust being distributed and terminated.

Can a person legally draw up a will leaving funds in his mother’s trust to other people prior to the trust being distributed and terminated? Would this be a legal will?