If this property was her primary residence at the time of her passing, then be aware that losses on the sale of personal property are never deductible. Period. Commonly when inheritied property is sold it's sold for an amount equal to the step up basis or less, thus resulting in no taxable gain. When sold for less than the step up basis, the loss is not deductible. Period. But at least you're not paying taxes on any gain that you may have "really" realized.
Another thing that matters in your specific case is the fact that your mom did not own the property - the estate did. So it matters on how the estate was set up in accordance with state law (not just federal law). But again, since the property was not being used for businses at the time of her passing, you basically have the sale of a 2nd home and any losses on the sale of that personal property are just flat out not deductible.
Overall, I would suggest you confer with an attorney on this, or better yet the attorney who set up the life estate. Overall I would not expect such an attorney to be all that knowledgeable on the tax side of things though. So a CPA or tax attorney might be better suited for this.
