When you inherit a piece of property or stock, etc it reevaluates on date of death. You really should not be paying capital gains on the house sale unless it appreciated a lot between her death and the sale. An accountant knows that.
And if the house was gifted, there is tax due upon the sale for capital gains between the date of gift value and sale value unless the gifted lived in the house. Because of life estate, it may make a difference.
I was just at a presentation Friday, the lawyer said this very thing, and this is what I have heard since 1995 when my father in law died and we had to start being careful about estates.
By the way, the lawyer who spoke was trying to scare everyone about taxes, and he mentioned that there have been proposals to do away with the stepped up basis upon death.