I'm filing a tax return for my mother who died 8/12/2015. I filed a return for her last year but still had the sale of her house. Help on deceased date and house.

You don't need to file a return for your mother.  In fact you can't file a 2016 Form 1040 for someone that passed away in 2015.  And unless she left an estate for which you would need to file an estate tax return, there's nothing to file for her.  When she passed away, her heirs (perhaps you) inherited the house.  The heir(s) would include the sale of the house on  their tax return.  If it was you that inherited the house, then your cost basis in the house would be the value of the house at the time of her death, less any expenses you incurred to get the house ready to sell or selling expenses such as seller paid closing costs.  If you have a gain, you have to report it.  If you have a loss you cannot deduct it.