You would use the step up.

Assuming this is NOT in a Community Property State, I generally recommend:

1. Split current assets into two new assets, each with the original "placed in service" date, 50% of their prior Basis (in your case, 25% of the total Basis), and 50% of their prior "prior depreciation" (in your case, 25% of the total prior).
2. Delete the old asset because you just replaced it with two 50% assets.
3. For the 50% asset that belonged to the husband, enter the date of death as the disposition date (leave the sales price BLANK).
4. Create another asset (the stepped up portion for the husband), using the FMV (50% of your clients total, or 25% of the complete total) using the date of death as the "placed in service" date.