If this was done as a life estate deed, (sometimes called a deed with reserved life estate), done many times to protect the asset
from medicaid availability, then the step-up in basis is retained, meaning the basis is the fair market value on date of death, as long as the home was sold after the life estate owner died.
If there was language in the deed that the house could not be sold without the assent of both the life AND remainder interest
holders you probably have a deed with reserved life estate.
Another clue would be that the life estate owner would have been advised
that if the home WERE sold during the life of the life estate owner it would not qualify for the exclusion of capital gain on sale.
On other clue would be that you would have been told that the property WOULD be included in the life estate owner's estate.
IF this is life estate deed, and you are the remainder interest owner, you do get a step-up in basis to the date of death fair market value.
If not, please tell me how the property was conveyed.