"My father had a a revocable trust at the time of his death. It was funded with a house, stocks and bonds. He died and the new trustees are three siblings. Will the cost basis for the stocks be from the date he died until the date the stocks were sold? He paid taxes on dividends as he received them every year."
Based on what you've said here all assets in the trust should get a stepped up basis to their value at the date of death.
Tom Young