Taxpayer passes away and creates an irrevocable trust. The income from the trust is distributed to his spouse with 2 sons as co-trustees. The mother passes and the lone asset is an Edward Jones account
It is more accurate to refer to an adjustment of basis to FMV, rather than a “step up”. It could be a step-down.
You need to determine who/what owned the property at time of death. An adjustment of basis to FMV applies to property inherited from an individual who died. A trust is neither an individual nor does it die. See Pub 551 for more information.