To answer your question more specifically, the sale would probably have to close no later than April 9, 2025, or maybe April 8. But as I said, don't cut it that close.
VolvoGirl got stepped up basis on the full value of her home because she lives in California, which is a community property state. If your friend is not in a community property state (or if the house was not held as community property) then the surviving spouse will only get stepped up basis on half the value. Their basis in the other half remains the same as it was before the other spouse's death. If the couple bought the house together, the surviving spouse's basis in their half is probably half of what the couple paid for the house, plus half the cost of any improvements.
