I am sorry for your loss.
First, the value of the securities in the brokerage account will be stepped up (or down) to their fair market value on the date of your dad's death (assuming this was a typical revocable trust). However, you will need to value each security, which is done by adding the high and low price on the day of his death and dividing by two (e.g., High of $50 per share, Low of $48 per share = $98 per share divided by 2 which equals a FMV of $49 per share).
Next, you need a thorough review of all of the documents. The assets in the trust will virtually always pass outside the will, which makes the will irrelevant in terms of who receives the trust assets. Who are the beneficiaries of the trust and are they the same as those named in the will?
If the trust sells the assets and distributes the proceeds then, generally, the beneficiaries will be responsible for paying any tax due on their share (to the extent of distributable net income). The governing instrument typically states how the assets are to be handled in terms of a sale, to whom the assets (or proceeds) are to be distributed, and whether or not the trust will pay any tax due.
